Washington (CNN) The United States is set to deploy troops on the ground in Syria for the first time to advise and assist rebel forces combating ISIS, the White House said Friday.

White House spokesman Josh Earnest said that the U.S. would be deploying "less than 50" Special Operations forces, who will be sent to Kurdish-controlled territory in northern Syria. The American troops will help local Kurdish and Arab forces fighting ISIS with logistics and are planning to bolster their efforts.

The deployment of U.S. Special Operations forces is the most significant escalation of the American military campaign against ISIS to date.

The Special Ops troops will first be deployed to northern Syria to help coordinate local ground forces and U.S.-led coalition efforts to fight ISIS, the senior administration official said. The local forces in that area have been the most effective U.S. partners in confronting ISIS.

White House Press Secretary Josh Earnest rejected early criticism that the small Special Ops force would not be sufficient, noting that they are an "important force multiplier anywhere around the world they are deployed."

"The President does expect that they can have an impact in intensifying our strategy for building the capacity of local forces inside of Syria for taking the fight on the ground to ISIL in their own country," Earnest said, using another acronym for ISIS. "That has been the core element of the military component of our strategy from the beginning: building the capacity of local forces on the ground."

Earnest said that this key element of U.S. strategy in confronting ISIS hasn't changed with Friday's announcement.

He was also careful to insist: "These forces do not have a combat mission."

The first group of Special Operations forces headed into northern Syria will come from the United States and could be on the ground within the month, according to a senior defense official.

Once the troops get there, they will be mainly based at an unofficial headquarters facility where representatives of Syrian Arabs, Kurds and other groups are located. The official would not disclose the location due to security concerns.

The troops will remain there for anywhere from weeks to months at a time, the official said.

The President has approved a current cap of less than 50 troops, with the first contingent expected to be about two dozen. But more could be sent, the official said.

These troops are not expected to go on raids or into combat, according to the current plan. However, they have the right of self-defense and could seek permission if needed to go into the field.

There will be additional Special Operations forces available for raids against targets in both Syria and Iraq when high-value ISIS targets are identified, the official said.

The U.S. support for the anti-ISIS fighters has a crucial goal of making them capable of challenging ISIS control of its unofficial capital, Raqqa. The effort is to make them able to isolate, take control, and "ultimately hold" the key city, the official said. There is no prediction of when that might be possible.

Photos: Syria's civil war, in pictures Photos: Syria's civil war, in pictures Displaced Syrian residents wait to receive food aid distributed by the UN Relief and Works Agency at the besieged al-Yarmouk camp, south of Damascus, Syria, on January 31, 2014. According to the UN Envoy for Syria, an estimated 400,000 Syrians have been killed since an uprising in March 2011 spiraled into civil war. See how the conflict has unfolded. Hide Caption 1 of 52 Photos: Syria's civil war, in pictures Hide Caption 2 of 52 Photos: Syria's civil war, in pictures An injured man lying in the back of a vehicle is rushed to a hospital in Daraa, Syria, on March 23, 2011. Violence flared in Daraa after a group of teens and children were arrested for writing political graffiti. Dozens of people were killed when security forces cracked down on demonstrations. Hide Caption 3 of 52 Photos: Syria's civil war, in pictures Anti-government protesters demonstrate in Daraa on March 23, 2011. In response to continuing protests, the Syrian government announced several plans to appease citizens. Hide Caption 4 of 52 Photos: Syria's civil war, in pictures Syrian children walk over bricks stored for road repairs during a spontaneous protest June 15, 2011, at a refugee camp near the Syrian border in Yayladagi, Turkey. Hide Caption 5 of 52 Photos: Syria's civil war, in pictures Jamal al-Wadi speaks in Istanbul on September 15, 2011, after an alignment of Syrian opposition leaders announced the creation of a Syrian National Council -- their bid to present a united front against Bashar al-Assad's regime and establish a democratic system. Hide Caption 6 of 52 Photos: Syria's civil war, in pictures Delegates from Arab League member states and Turkey discuss a response to the government's crackdown in Syria on November 16, 2011. Hide Caption 7 of 52 Photos: Syria's civil war, in pictures Supporters of al-Assad celebrate during a referendum vote in Damascus on February 26, 2012. Opposition activists reported at least 55 deaths across the country as Syrians headed to the polls. Analysts and protesters widely described the constitutional referendum as a farce. "Essentially, what (al-Assad's) done here is put a piece of paper that he controls to a vote that he controls so that he can try and maintain control," a US State Department spokeswoman said. Hide Caption 8 of 52 Photos: Syria's civil war, in pictures Syrian refugees walk across a field in Syria before crossing into Turkey on March 14, 2012. Hide Caption 9 of 52 Photos: Syria's civil war, in pictures Rebel fighters with the Free Syrian Army capture a police officer in Aleppo, Syria, who they believed to be pro-regime militiaman on July 31, 2012. Dozens of officers were reportedly killed as rebels seized police stations in the city. Hide Caption 10 of 52 Photos: Syria's civil war, in pictures A Free Syrian Army fighter runs for cover as a Syrian Army tank shell hits a building across the street during clashes in the Salaheddine neighborhood of central Aleppo on August 17, 2012. Hide Caption 11 of 52 Photos: Syria's civil war, in pictures Family members mourn the deaths of their relatives in front of a field hospital in Aleppo on August 21, 2012. Hide Caption 12 of 52 Photos: Syria's civil war, in pictures A Syrian man carrying grocery bags dodges sniper fire in Aleppo as he runs through an alley near a checkpoint manned by the Free Syrian Army on September 14, 2012. Hide Caption 13 of 52 Photos: Syria's civil war, in pictures Free Syrian Army fighters are reflected in a mirror they use to see a Syrian Army post only 50 meters away in Aleppo on September 16, 2012. Hide Caption 14 of 52 Photos: Syria's civil war, in pictures Smoke rises over the streets after a mortar bomb from Syria landed in the Turkish border village of Akcakale on October 3, 2012. Five people were killed. In response, Turkey fired on Syrian targets and its parliament authorized a resolution giving the government permission to deploy soldiers to foreign countries. Hide Caption 15 of 52 Photos: Syria's civil war, in pictures A Syrian rebel walks inside a burnt section of the Umayyad Mosque in Aleppo hours before the Syrian army retook control of the complex on October 14, 2012. Hide Caption 16 of 52 Photos: Syria's civil war, in pictures An Israeli tank crew sits on the Golan Heights overlooking the Syrian village of Breqa on November 6, 2012. Israel fired warning shots toward Syria after a mortar shell hit an Israeli military post. It was the first time Israel fired on Syria across the Golan Heights since the 1973 Yom Kippur War. Hide Caption 17 of 52 Photos: Syria's civil war, in pictures Smoke rises in the Hanano and Bustan al-Basha districts in Aleppo as fighting continues through the night on December 1, 2012. Hide Caption 18 of 52 Photos: Syria's civil war, in pictures The bodies of three children are laid out for identification by family members at a makeshift hospital in Aleppo on December 2, 2012. The children were allegedly killed in a mortar shell attack that landed close to a bakery in the city. Hide Caption 19 of 52 Photos: Syria's civil war, in pictures A father reacts after the deaths of two of his children in Aleppo on January 3, 2013. Hide Caption 20 of 52 Photos: Syria's civil war, in pictures Syrians look for survivors amid the rubble of a building targeted by a missile in the al-Mashhad neighborhood of Aleppo on January 7, 2013. Hide Caption 21 of 52 Photos: Syria's civil war, in pictures Rebels launch a missile near the Abu Baker brigade in Al-Bab, Syria, on January 16, 2013. Hide Caption 22 of 52 Photos: Syria's civil war, in pictures An aerial view shows the Zaatari refugee camp near the Jordanian city of Mafraq on July 18, 2013. Hide Caption 23 of 52 Photos: Syria's civil war, in pictures The UN Security Council passes a resolution September 27, 2013, requiring Syria to eliminate its arsenal of chemical weapons. Al-Assad said he would abide by the resolution. Hide Caption 24 of 52 Photos: Syria's civil war, in pictures Residents run from a fire at a gasoline and oil shop in Aleppo's Bustan Al-Qasr neighborhood on October 20, 2013. Witnesses said the fire was caused by a bullet from a pro-government sniper. Hide Caption 25 of 52 Photos: Syria's civil war, in pictures Syrian children wait as doctors perform medical checkups at a refugee center in Sofia, Bulgaria, on October 26, 2013. Hide Caption 26 of 52 Photos: Syria's civil war, in pictures An injured man is helped following an airstrike in Aleppo's Maadi neighborhood on December 17, 2013. Hide Caption 27 of 52 Photos: Syria's civil war, in pictures A man holds a baby who was rescued from rubble after an airstrike in Aleppo on February 14, 2014. Hide Caption 28 of 52 Photos: Syria's civil war, in pictures A US ship staff member wears personal protective equipment at a naval airbase in Rota, Spain, on April 10, 2014. A former container vessel was fitted out with at least $10 million of gear to let it take on about 560 metric tons of Syria's most dangerous chemical agents and sail them out to sea, officials said. Hide Caption 29 of 52 Photos: Syria's civil war, in pictures A Free Syrian Army fighter fires a rocket-propelled grenade during heavy clashes in Aleppo on April 27, 2014. Hide Caption 30 of 52 Photos: Syria's civil war, in pictures A giant poster of al-Assad is seen in Damascus on May 31, 2014, ahead of the country's presidential elections. He received 88.7% of the vote in the country's first election after the civil war broke out. Hide Caption 31 of 52 Photos: Syria's civil war, in pictures Rebel fighters execute two men on July 25, 2014, in Binnish, Syria. The men were reportedly charged by an Islamic religious court with detonating several car bombs. Hide Caption 32 of 52 Photos: Syria's civil war, in pictures Photographs of victims of the Assad regime are displayed as a Syrian army defector known as "Caesar," center, appears in disguise to speak before the House Foreign Affairs Committee in Washington. The July 31, 2014, briefing was called "Assad's Killing Machine Exposed: Implications for U.S. Policy." Caesar, apparently a witness to the regime's brutality, smuggled more than 50,000 photographs depicting the torture and execution of more than 10,000 dissidents. CNN cannot independently confirm the authenticity of the photos, documents and testimony referenced in the report. Hide Caption 33 of 52 Photos: Syria's civil war, in pictures Volunteers remove a dead body from under debris after shelling in Aleppo on August 29, 2014. According to the Syrian Civil Defense, barrel bombs are now the greatest killer of civilians in many parts of Syria. The White Helmets are a humanitarian organization that tries to save lives and offer relief. Hide Caption 34 of 52 Photos: Syria's civil war, in pictures Medics tend to a man's injuries at a field hospital in Douma after airstrikes on September 20, 2014. Hide Caption 35 of 52 Photos: Syria's civil war, in pictures A long-exposure photograph shows a rocket being launched in Aleppo on October 5, 2014. Hide Caption 36 of 52 Photos: Syria's civil war, in pictures Rebel fighters dig caves in the mountains for bomb shelters in the northern countryside of Hama on March 9, 2015. Hide Caption 37 of 52 Photos: Syria's civil war, in pictures Nusra Front fighters inspect a helicopter belonging to pro-government forces after it crashed in the rebel-held Idlib countryside on March 22, 2015. Hide Caption 38 of 52 Photos: Syria's civil war, in pictures A Syrian child fleeing the war gets lifted over fences to enter Turkish territory illegally near a border crossing at Akcakale, Turkey, on June 14, 2015. Hide Caption 39 of 52 Photos: Syria's civil war, in pictures A refugee carries mattresses as he re-enters Syria from Turkey on June 22, 2015, after Kurdish People's Protection Units regained control of the area around Tal Abyad, Syria, from ISIS. Hide Caption 40 of 52 Photos: Syria's civil war, in pictures A sandstorm blows over damaged buildings in the rebel-held area of Douma, east of Damascus, on September 7, 2015. Hide Caption 41 of 52 Photos: Syria's civil war, in pictures Members of a Syrian opposition group attack the headquarters of al-Assad regime forces in the Aleppo villages of Nubul and al-Zahraa on February 12, 2016. Hide Caption 42 of 52 Photos: Syria's civil war, in pictures This still image, taken from a video posted by the Aleppo Media Center, shows a young boy in an ambulance after an airstrike in Aleppo, Syria, on August 17, 2016. It took nearly an hour to dig the boy, identified as Omran Daqneesh, out from the rubble, an activist told CNN. The airstrike destroyed his home, where he lived with his parents and two siblings. Director of the Aleppo Media Center Yousef Saddiq said Omran's 10-year-old brother, Ali, died from his injuries. Hide Caption 43 of 52 Photos: Syria's civil war, in pictures Smoke rises after an airstrike in Aleppo on October 4, 2016. Hide Caption 44 of 52 Photos: Syria's civil war, in pictures Arabic writing that reads "some day we will return" is seen on a bus window as civilians evacuate Aleppo on December 15, 2016. The evacuations began under a new ceasefire between rebels and pro-government forces. Hide Caption 45 of 52 Photos: Syria's civil war, in pictures This photo, provided by the activist Idlib Media Center, shows dead children after a suspected chemical attack in the rebel-held city of Khan Sheikhoun on April 4, 2017. Dozens of people were killed, according to multiple activist groups. The United States responded a few days later by launching between 50-60 Tomahawk missiles at a Syrian government airbase. US officials said the base was home to warplanes that carried out the chemical attack. Syria has repeatedly denied it had anything to do with the attack. Hide Caption 46 of 52 Photos: Syria's civil war, in pictures Members of the UN Security Council raise their hands on April 12, 2017, as they vote in favor of a draft resolution that condemned the reported use of chemical weapons in Syria. Hide Caption 47 of 52 Photos: Syria's civil war, in pictures Residents of the war-torn city of Douma break their Ramadan fast on June 18, 2017. Hide Caption 48 of 52 Photos: Syria's civil war, in pictures A member of the Syrian pro-regime forces fires a machine gun as a comrade holds his feeding ammunition belt on November 11, 2017. It was during an advance toward rebel-held positions west of Aleppo. Hide Caption 49 of 52 Photos: Syria's civil war, in pictures A child receives medical treatment after a village was attacked in the rebel-held Eastern Ghouta region on February 25, 2018. Several people were treated for exposure to chlorine gas, opposition groups said, as airstrikes and artillery fire from the regime continued. CNN was unable to independently verify claims that chlorine was used as a weapon. Hide Caption 50 of 52 Photos: Syria's civil war, in pictures Bodies lie on the ground in the rebel-held city of Douma, Syria, on April 8, 2018. According to activist groups, helicopters dropped barrel bombs filled with toxic gas on Douma, which has been the focus of a renewed government offensive that launched in mid-February. The Syrian government and its key ally, Russia, vehemently denied involvement and accused rebel groups of fabricating the attack to hinder the army's advances and provoke international military intervention. Hide Caption 51 of 52 Photos: Syria's civil war, in pictures Damascus skies erupt with anti-aircraft fire as the US and its allies launch an attack on Syria's capital early on April 14, 2018. US President Donald Trump announced airstrikes in retaliation for Syria's alleged use of chemical weapons. Trump says the strikes are part of a sustained military response, in coordination with France and the United Kingdom. Hide Caption 52 of 52

The U.S. will also boost its military footprint in confronting ISIS in Syria by deploying A-10 and F-15 fighter jets to Incirlik Air Base in Turkey. And the U.S. is also eying the establishment of a Special Forces task force in Iraq to boost U.S. efforts to target ISIS and its leaders, the administration official said. President Barack Obama has also authorized enhancing military aid to Jordan and Lebanon to help counter ISIS.

America has bombed targets in Syria since September 2014 without stopping ISIS, and it has largely failed in a mission to recruit and train moderate rebels in Syria to take on the terror group. In recent months, the U.S. has also bolstered its aid to local forces, air-dropping weapons, ammunition and other supplies to rebel forces inside Syria.

Obama has long resisted an American military presence on the ground to combat ISIS in Iraq and Syria but has reluctantly escalated U.S. involvement in that fight over time since launching the military effort in 2014.

The number of U.S. military forces in Iraq has swelled to more than 3,500 since Obama first announced the deployment of up to 300 American military advisers to Iraq in June 2014.

U.S. Special Ops have previously conducted some secretive missions on the ground in Syria as well. But the deployment marks the first permanent presence of U.S. ground troops in Syria since the U.S. began leading an international effort last year to confront ISIS, the militant Islamist group which now controls broad swaths of territory in Iraq and Syria.

The troops are set to be deployed to Syria in the coming days, according to these officials.

The decision comes on the heels of the first death of an American military service member in the fight against ISIS. Master Sgt. Joshua Wheeler died last week in Iraq as he and other American Special Operations forces conducted a raid to rescue hostages held by ISIS.

The troops to be sent to Syria are not expected to serve on the front lines with rebel forces and, according to a U.S. official, they will rotate in and out of Syria from the existing U.S. base in Irbil, Iraq.

But they are entering a very hot combat zone and have the right to engage the enemy if they come under fire. They could also join Syrian and Kurdish forces on raids if they get explicit permission from Washington.

The Syrian Kurdish fighting force in northern Syria welcomed the decision to deploy U.S. troops to assist them but reiterated the need for more assistance and weaponry to fight ISIS.

"We have experience fighting ISIS and I think the whole world has seen as evidence of that the areas that we currently hold in Syria. We hope that this assistance will evolve from all our different friends and allies. We need all types of assistance but first and foremost weapons are primarily our most important need," said Mohamed Rasho, spokesman for the political wing of the YPG, the Syrian Kurd fighting force.

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The stepped-up U.S. military involvement in Syria also comes amid a redoubling of diplomatic efforts to reach a resolution to the multi-year conflict between the Syrian government and rebel forces, which ISIS has exploited to expand its base in the country.

U.S. Secretary of State John Kerry has been holding meetings in recent days with U.S. allies in the region and recently agreed to give Iran a role in the peace talks, which also include Russia, Turkey, Iraq, Lebanon, Egypt and Saudi Arabia.

Iran and Russia have supported the regime of Syrian President Bashar al-Assad even as Assad has been accused of committing war crimes against his own people, including the indiscriminate bombing of civilian areas.

Russia entered the military fray earlier this month by deploying forces to Syria and launching a bombing campaign that it claims has been targeting ISIS. But the locations of Russian airstrikes have led U.S. military officials to say they believe the Russian effort is aimed more at bolstering Assad's hold on power than fighting ISIS.

Russia's military involvement in Syria has been greeted in Washington with a mixture of caution and criticism, with Obama warning Russia earlier this month that its airstrikes in Syria would suck it into a "quagmire."

Director of National Intelligence James Clapper told CNN Thursday that he believed Russian President Vladimir Putin didn't have a long-term plan for his country's military involvement in Syria, saying he thinks "he is kind of winging this day to day."

The U.S. and Russia have in recent weeks held a series of deconfliction talks to find ways to prevent accidents or misunderstandings between U.S. and Russian jets sharing the skies over Syria.

Russian jets, though, have not been operating in the skies above northern Syria where the U.S. is now deploying ground forces.

Obama has faced steady and unrelenting criticism of his leadership in the fight against ISIS, with Republicans and even some Democrats consistently accusing him of lacking any clear strategy to fight the militant Islamist group, which has threatened attacks against the U.S.

House Armed Services Committee Chairman Mac Thornberry, a Texas Republican, gave a tempered response Obama's decision to send ground troops to Syria.

"A more serious effort against ISIS in Syria is long overdue," he said in a statement Friday. "Absent a larger coherent strategy, however, these steps may prove to be too little too late. I do not see a strategy for success, rather it seems the Administration is trying to avoid a disaster while the President runs out the clock."

Democratic Sen. Tim Kaine of Virginia, who has also called for a more aggressive approach, said Friday in a statement that it is "time for the Administration to propose a unified strategy that addresses the intertwined challenges posed by ISIL and President Assad," with Friday's decision only addressing "half the problem -- ISIL, but not Assad."

Kaine also renewed his calls for Congress to vote on an authorization of the use of military force against ISIS, which it has yet to do. The U.S. has been acting in Syria and Iraq on legal grounds based in the authorization of military force against al Qaeda elements.

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2016ers weigh in

Sen. Bernie Sanders "expressed concern" over Obama's decision in a statement Friday evening.

"Sen. Sanders expressed concern about the United States being drawn into the quagmire of the Syrian civil war which could lead to perpetual warfare in that region," spokesman Michael Briggs said. "The senator believes that the crisis in Syria will be solved diplomatically, not militarily."

Sen. Lindsey Graham of South Carolina, who has staked his presidential campaign on his hawkish foreign policy views, called the decision to deploy Special Operations forces "an incremental change that will not change the conditions on the ground."

"In the eyes of the enemy this is weakness. In the eyes of our allies this is unreliability. ISIL is not going to be intimidated by this move," Graham said Friday on MSNBC. "You know, they're all in for their agenda: the caliphate and their view of the world. President Obama is not all in when it comes to degrading and destroying ISIL and this just reinforces that."

Graham also renewed his calls for a no-fly zone over Syria to address the refugee problem and to properly train rebel forces.

GOP presidential contenders have called for everything from tens of thousands of U.S. troops to be deployed to Iraq to the establishment of a no-fly zone over Syria.

In an interview with CNN last week, Florida Sen. Marco Rubio, a GOP presidential candidate, called not just for the establishment of a no-fly zone but also a safe zone where moderate rebels "can organize, train, equip and ultimately present a credible alternative to Assad for the future of Syria."

Rubio also called for Special Operations forces to be embedded with local forces.

"Only America can convene Sunni forces from what I believe needs to be a combined Sunni force of Egyptians, Saudis, Jordanians, Sunnis in Iraq, Sunnis in Syria to confront a radical Sunni movement and defeat them militarily. They will need our help in convening it," Rubio told CNN's Jamie Gangel. "But it doesn't involve a full-scale U.S. invasion of Iraq."