With the Islamic State collapsing in Iraq and losing ground in Syria, Iran and its regional proxies see the United States as the primary threat to their influence and ambitions and have stepped up efforts to oust the U.S. military from the region. Through diplomatic outreach – and at times veiled threats – Iranian leaders have been urging the Afghan and Iraqi governments to expel American forces from their countries. Tehran has also deepened its ties with the Taliban and has reportedly teamed up with Moscow to undermine U.S.-led stabilization efforts in war-torn Afghanistan. In Iraq, Iranian-supported paramilitary forces have dialed up propaganda against the United States and its allies and are pressuring the Baghdad government to expel American forces from the country. Likewise in Syria, the Islamic Revolution Guards Corps (I.R.G.C.) and its regional Shiite militia affiliates increasingly threaten the U.S. military and its allies. Moreover, the I.R.G.C. naval forces frequently harass U.S. ships in the Persian Gulf, and Iran’s political and military leaders have ratchet up hostile rhetoric against U.S. military bases in the Middle East.

Undermining U.S. mission in Afghanistan

On Tuesday, Iranian Parliament Speaker Ali Larijani told his Afghan counterpart Abdul Rauf Ibrahimi that “there is no need for the presence of foreign military forces in Afghanistan” and pledged that Iran was ready to help Kabul tackle its security challenges. “The people of Afghanistan are able to deal with them [terrorists], and the presence of foreign troops under the pretext of fighting terrorism has hindered Afghanistan’s development,” the top Iranian lawmaker said. “Iran will do anything it can to help Afghanistan combat terrorism,” he added.

Although Tehran does not want the Taliban – Shiite Iran’s ideological foe – to return to power in Afghanistan, it sees the presence of American troops along its eastern border as a bigger threat. And as tension between Washington and Tehran is escalating over the latter’s ballistic missile program and support for terrorism, the I.R.G.C. has stepped up its funding, sheltering and training Taliban fighters to create trouble for the U.S. military and force it to leave Afghanistan.

Much of Iran’s support to the Taliban has geographically been confined to western and southern Afghanistan. But recent reports in the Afghan media suggest the I.R.G.C. may have expanded its support to Taliban fighters to eastern and northern Afghanistan as well. On May 30, Afghan security forces said they had seized Iranian-made weapons from the Taliban in Paktika, a restive province in southeastern Afghanistan where the dangerous Haqqani Network wields significant influence. “I know all types of weapons but saw such arms for the first time. Iranian stamps are visible on them,” a local police chief told Pajhwok News Agency.

Afghan and American officials also say Iran has set up new training camps for Taliban fighters along Afghanistan’s border and has delivered Russian arms to the insurgents in western and southern Afghan provinces.

Expelling U.S. forces from Iraq

Iran and the United States have been de facto allies in the fight against the Islamic State in Iraq since 2014. Although Washington and Tehran have not directly coordinated their efforts in Iraq, the U.S. military has provided air and logistical support to Iraqi ground operations involving Iranian-backed units of the Iraqi Popular Mobilization Forces (P.M.F.). But as the common enemy is losing Mosul, Iran and its allies have already shifted attention to the U.S. presence and role in Iraq.

Last week, Supreme Leader Ali Khamenei said Iran opposed the presence of American forces in Iraq and urged the Iraqi prime minister not to rely on Washington. “Do not trust the Americans under any circumstances because they are waiting for an opportunity to do harm,” the supreme leader told Haider al-Abadi at a meeting in Tehran. Khamenei accused the United States of sowing discord in Iraq for its geopolitical interests and added: “They should not be given this opportunity. Also, the deployment of American forces to Iraq under the pretext of training and other matters should be avoided.” The top Iranian leader also voiced support for P.M.F. and cautioned the Iraqi prime minister not to listen to American advice on weakening or disbanding the force after the defeat of the Islamic State.

Moreover, Iranian-backed P.M.F. units have also intensified propaganda against the U.S., which poses security risks to American military advisers that are helping the Iraqi security forces in the country. P.M.F. commanders increasingly accuse the U.S. and its allies of aiding the Islamic State and they pressure the Baghdad government to “expel” American forces from the country. “The international coalition has not assisted Iraq other than killing civilians and helping terrorists,” P.M.F. Spokesman Ali al-Husseini said in an interview with I.R.G.C.-affiliated Fars News Agency. “The coalition has also had a role in supporting Daesh [Islamic State]. In addition to providing military and logistical aid to this terrorist group, it has also played a role in helping its members to escape,” he further alleged. “The Iraqi Popular Mobilization urges the Baghdad government to expel the international coalition from the Mosul battle and oppose Pentagon’s deployment of more American soldiers to Iraq,” he stressed.

The latest escalation in propaganda raises the fear that the Iranian proxies may revert to their pre-Islamic State sabotage actions against the U.S. and its interests in Iraq and the broader region.

Confronting U.S. in Syria

In Syria, the I.R.G.C. has recently deployed thousands of Lebanese Hezbollah fighters as well as Iraqi and Afghan militiamen to southern and eastern Syria to challenge the presence of American troops in al-Tanf region along Syria’s borders with Iraq and Jordan, and to prevent U.S.-backed Syrian rebel forces from moving toward the eastern Syrian province of Deir Ez-Zor. Earlier this month, an Iranian-made drone fired on al-Tanf, provoking the U.S. military to strike back and destroy it. Last month, U.S. forces also launched an air strike against an Iranian-directed convoy approaching coalition forces near al-Tanf area. I.R.G.C. media outlets emphasize that pro-Damascus militia groups will continue to defy U.S. threats and expand the writ of the Syrian government in the south and east.

Two weeks ago, Iranian outlets reported that Shiite militia groups in Iraq and Syria finally linked up along the shared border between the two countries. This not only helps Iran’s plan to build a land corridor to Lebanon through Syria and Iraq, but also to prevent U.S.-backed Syrian rebel forces in the south and north to link up in eastern Syria. Although U.S. military officials insist that they have no desire to confront Damascus and its foreign allies, the potential for flashpoints for confrontation between pro-regime forces and U.S. military and its allies will significantly increase as all parties are trying to squeeze more territory from the Islamic State in eastern Syria.

Tension in Persian Gulf

U.S. military officials complain that I.R.G.C. naval forces regularly harass U.S. ships in international waters in the Persian Gulf and caution that such Iranian behavior might lead to miscalculations and dangerous confrontations in the future. On June 14, U.S. officials said that three U.S. Navy ships and a Marine helicopter had an “unsafe and unprofessional” encounter with an Iranian Navy vessel that came within 800 yards of a U.S. amphibious assault ship U.S.S. Bataan in the Strait of Hormuz. The Iranian boat also shined a laser at the U.S. helicopter accompanying the ships.

In late April, American officials said that a U.S. Navy guided-missile destroyer fired a warning flare to deter an I.R.G.C. vessel approaching it in the Persian Gulf. Iran’s Foreign Minister Javad Zarif took to Twitter to defend the I.R.G.C.’s move: "Breaking: Our Navy operates in — yes, correct — the Persian Gulf, not the Gulf of Mexico. Question is what US Navy doing 7,500 miles from home," he tweeted, also attaching a map showing a distance of 7,592 miles between the Persian Gulf and Miami.

In March, Centcom commander Gen. Joseph Votel told the U.S. Congress that the I.R.G.C. naval forces had increased their “unprofessional, unsafe and abnormal” maritime activities. "We have to hold Iran accountable,” he stressed. His comment came just days after the I.R.G.C. had sent fast-attack boats close to the U.S.N.S. Invincible in the Strait of Hormuz, forcing the U.S. ship to change course. In reaction to Votel’s remarks, Iran's Defense Minister Hossein Dehghan called on Washington to leave the region. “What are the Americans doing in the Persian Gulf? It is better they leave this region and do not create trouble for the regional countries,” he said. “Is it acceptable that an armed, insane thief breaks into someone’s house and expects the red carpet to be rolled out for him?”

Recently, senior Iranian officials have also threatened to attack Israel and U.S. bases in the Middle East if Washington “makes any mistakes” toward Iran. “The Fifth Fleet of the U.S. Army has occupied a part of Bahrain, and the farthest military base of the enemy is stationed in the Indian Ocean. But these locations are within the reach of Iranian missiles. If the enemy makes a mistake, they will be razed to the ground,” said Mojtaba Zonour, who has also served as an advisor to the Supreme Leader Ali Khamenei to the I.R.G.C. in the past.