Story highlights U.S. threats against Syria are "unacceptable," Russian official says

Source: No final U.N. report on Syria inspection likely for a week

President Obama still deciding on a U.S. response to Syria's "challenge to the world"

U.N. inspectors start leaving Syria with evidence from sites of the Aug. 21 attack

Declaring himself "war-weary" but determined to hold Syria accountable for using banned chemical weapons, President Barack Obama said Friday he was considering a limited response to what U.S. intelligence assessed with "high confidence" as a Syrian attack that killed more than 1,400 people.

Obama told reporters he had yet to make a final decision, but hinted at a military strike that sources and experts say would entail cruise missiles fired from U.S. Navy ships at Syrian command targets -- but not at any chemical weapons stockpiles.

"It is not in the national security interests of the United States to ignore clear violations" of what he called an "international norm" banning the use of chemical weapons, Obama said at a meeting with visiting heads of Baltic nations Lithuania, Latvia and Estonia.

He called the Syrian attack a "challenge to the world" that threatens U.S. allies Israel, Turkey and Jordan while increasing the risk of such weapons falling into the hands of terrorists.

President Bashar al-Assad's government has claimed that jihadists fighting with the rebels carried out the chemical weapons attacks on August 21 to turn global sentiments against it, a claim dismissed by Obama and others who say there is no evidence to support that claim.

Earlier, Secretary of State John Kerry released details of a declassified U.S. intelligence report in an effort to muster support at home and abroad for a military response against al-Assad's government.

Obama's preference

However, NATO allies want the United Nations to authorize any military response, something that both Kerry and Obama said was unlikely because of opposition by permanent Security Council member Russia, a Syrian ally.

"My preference would have been that the international community already would have acted," Obama said, citing "the inability of the Security Council to move in the face of a clear violation of international norms."

Photos: Photos: Suspected chemical attack in Syria Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – A convoy of inspectors from the Organisation for the Prohibition of Chemical Weapons prepares to cross into Syria at the Lebanese border crossing point of Masnaa on Tuesday, October 1. Inspectors from the Netherlands-based watchdog arrived in Syria to begin their complex mission of finding, dismantling and ultimately destroying Syria's chemical weapons arsenal. Hide Caption 1 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – The U.N. Security Council votes to approve a resolution that will require Syria to give up its chemical weapons during a meeting on Friday, September 27. The vote came after assertions by the United States and other Western nations that the Syrian government used chemical weapons in an August 21 attack outside Damascus that U.S. officials estimate killed 1,400 people. Hide Caption 2 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – U.S. Secretary of State John Kerry said the world community was imposing a binding obligation on the government of Syrian President Bashar al-Assad to get rid of its chemical weapons stockpile. Hide Caption 3 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – A man mourns over the bodies of those killed in a suspected chemical weapon attack in a suburb of Damascus, Syria, on Wednesday, August 21. Syrian rebels said poisonous gas rained down from rockets, but authorities have denied the allegations that they used chemical weapons and accused the opposition of staging the attacks. U.S. officials, however, said there were "strong indications" that there was a chemical weapons attack by the government. Hide Caption 4 of 17 Photos: Photos: Suspected chemical attack in Syria Hide Caption 5 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – People attend to the victims of the attack on August 21 in Damascus. British intelligence said at least 350 people died, while rebel leaders have put the death toll at more than 1,300. Hide Caption 6 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Constricted pupils was listed as a symptom in victims of the alleged attack on August 21. Hide Caption 7 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Victims of the attack are laid in the back of a truck in the Hamoria area of Damascus on August 21. Hide Caption 8 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – A young survivor takes shelter in a mosque in the Duma neighborhood of Damascus on August 21. Hide Caption 9 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Victims are buried in a suburb of Damascus on August 21. Hide Caption 10 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – People search for the dead to collect samples to check for chemical weapon use in the Zamalka area of Syria on Thursday, August 22. Hide Caption 11 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – A group of young Salafists chants and waves black flags during a protest against the Egyptian and Syria regimes in the southern Gaza Strip on August 22. Hide Caption 12 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – A young woman holds a Syrian revolution flag and a candle during a protest of President Bashar al-Assad in front of the U.N. headquarters in Gaza City on Friday, August 23. U.N. Secretary-General Ban Ki-moon intends to conduct a "thorough, impartial and prompt investigation" into the alleged chemical weapons attack in Syria. Hide Caption 13 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Pigeons' bodies litter the ground in the Damascus suburbs of Arbeen on Saturday, August 24. Hide Caption 14 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Syrian soldiers are deployed in the Jobar neighborhood of Damascus on August 24. Hide Caption 15 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Syrian President Bashar al-Assad speaks with the Russian newspaper Izvestia in Damascus, Syria, on Monday, August 26. He told the newspaper that Western accusations that the Syrian government used chemical weapons are an insult to common sense. Hide Caption 16 of 17 Photos: Photos: Suspected chemical attack in Syria Suspected chemical attack in Syria – Representatives of Arab countries discuss Syria at the Arab League headquarters in Cairo, Egypt, on Tuesday, August 27. President al-Assad vowed to defend his country against any outside attack. "The threats of launching an aggression against Syria will increase its commitments," and "Syria will defend itself against any aggression," he said, according to Syrian state TV. Hide Caption 17 of 17

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He expressed frustration with the lack of international support, saying that "a lot of people think something should be done, but nobody seems willing to do it."

"It's important for us to recognize that when over 1,000 people are killed, including hundreds of innocent children, through the use of a weapon that 98 or 99 percent of humanity says should not be used even in war, and there is no action, then we're sending a signal that that international norm doesn't mean much," Obama said. "And that is a danger to our national security."

Russian Foreign Minister Alexander Lukashevich dismissed the threats by the United States as "unacceptable."

"Washington's statements threatening to apply force to Syria are unacceptable," Lukashevich said in a statement posted on the ministry's website. He added that United Nations weapons inspectors are still investigating and "without any proof we are hearing threats of striking Syria."

"Even U.S. allies have called for 'taking a break' to wait for the U.N. experts to complete their work in order to get an objective picture of what happened there," he said.

Rising resistance

The remarks by Obama and Kerry, and the release of the intelligence report, came as Obama's administration faced rising resistance to a military strike against the Syrian government both at home and abroad.

Britain's Parliament voted against joining a coalition sought by Obama to respond militarily, denying the president a key NATO ally that has steadfastly supported previous campaigns.

In Washington, questions about the veracity of the U.S. intelligence and whether the nation is headed for another long war based on false information -- like happened in Iraq -- have emerged from both parties in Congress.

"I assure you nobody ends up being more war-weary than me," Obama said, adding that he was not considering any option that would entail "boots on the ground" or a long-term campaign.

Instead, Obama said, he and his top military and security aides were looking at a "limited, narrow act" to ensure that Syria and others know the United States and its allies won't tolerate future similar future violations.

For almost two years, Obama has avoided direct military involvement in Syria's civil war, only escalating aid to rebel fighters in June after suspected smaller-scale chemical weapons attacks by Syrian government forces.

However, last week's attack obliterated the "red line" Obama set just over a year ago against the use of Syria's chemical weapons stocks.

Veteran Republican Sens. John McCain of Arizona and Lindsey Graham of South Carolina challenged Obama's plan Friday, issuing a statement that said the purpose of any U.S. military action in Syria "should not be to help the president save face."

The goal, they said, "should be to shift the balance of power on the battlefield against Assad and his forces."

Kerry: "We will not repeat" Iraq

Earlier, Kerry insisted that the situation differs from Iraq, saying the intelligence community "reviewed and re-reviewed" its information "more than mindful of the Iraq experience." And he added: "We will not repeat that moment."

He cited particular evidence that he insisted shows al-Assad's regime was responsible.

"We know that for three days before the attack, the Syrian regime's chemical weapons personnel were on the ground in the area, making preparations," Kerry said. "And we know that the Syrian regime elements were told to prepare for the attack by putting on gas masks and taking precautions associated with chemical weapons."

Additionally, the intelligence shows the day, time and location of the rockets that were launched and where and when they landed.

"We know rockets came only from regime-controlled areas and went only to opposition-controlled or contested neighborhoods," he said.

Quoting from the U.S. assessment, Kerry said the attack killed 1,429 people, including more than 400 children.

On Friday, the Syrian government called the U.S. intelligence information "old tales" based on "fabrications and lies."

'We are not alone'

Citing support from the Arab League, Turkey and France, Kerry said, "We are not alone in our will to do something" in response to the attack. He brushed off the British Parliament vote against joining a military invention, saying that the United States "makes our own decisions on our own timelines, based on our values and our interests" in deciding the proper course of action.

Meanwhile, the U.N. mission investigating the suspected chemical weapons attack in Syria has completed its collection of samples, said Martin Nesirky, spokesman for U.N. Secretary-General Ban Ki-moon.

Nesirky told reporters that inspectors visited a government military hospital in Damascus and the last of them will leave Syria on Saturday.

Ban will get a briefing Saturday from the inspectors, but a Western diplomat told CNN that the secretary-general would likely wait to meet again with the Security Council until a final report with laboratory analysis is completed, which could take a week.

Even as the U.N. inspection was winding down, opposition activists said Friday there is evidence of another deadly assault in Syria involving an incendiary agent. Seven people died and dozens were injured Monday in the attack on a school in northern Syria.

So far, opposition by Russia to any military response has scuttled U.N. action, and Kerry expressed little hope for a breakthrough.

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"Because of the guaranteed Russian obstructionism of any action through the U.N. Security Council, the U.N. cannot galvanize the world to act as it should," he said.

Later Friday, Obama spoke by phone with French President Francois Hollande and British Prime Minister David Cameron. White House statements said in both calls, the leaders agreed the Syrian violation of chemical weapons bans cannot be tolerated, but only the statement on the call with Hollande said they agreed the Syrian regime must be held accountable.

While the British vote was a blow to Obama's hopes of getting strong support from key NATO allies and some Arab League states, regional NATO ally Turkey on Friday backed the U.S. contention that al-Assad's regime was responsible for the chemical attack.

"The information at hand indicates that the opposition does not have these types of sophisticated weapons," said Foreign Minister Ahmet Davutoglu. "From our perspective, there is no doubt that the regime is responsible."

Australia also weighed in, with Prime Minister Kevin Rudd saying the evidence against al-Assad was overwhelming and, "therefore, the focus now legitimately lies on the most appropriate from of international response."

Rudd said there has been "no request from the United States or any other country for a direct or indirect Australian military participation" in a possible strike against Syria.

Alone or together?

The White House has made clear that the United States will respond in some form to the use of chemical weapons. Previously, it ruled out U.S. troops on the ground or imposing a no-fly zone.

Sources have indicated a campaign of limited strikes by cruise missiles fired from U.S. naval ships in the region, targeting military command centers but not chemical weapons stockpiles, is the likely option.

The British Parliament vote and demands by other key European allies, including France and Germany, to put off a decision until after the U.N. inspectors report on what happened in Syria have slowed the response time.

Hollande told Le Monde newspaper that intervention should be limited and not be directed toward al-Assad's overthrow, a position also expressed by Obama.

Also Friday, former President Jimmy Carter, said "a punitive military response without a U.N. Security Council mandate or broad support from NATO and the Arab League would be illegal under international law and unlikely to alter the course of the war."

Defense Secretary Chuck Hagel has repeatedly said the United States will respond to Syria in concert with allies.

"Our approach is to continue to find an international coalition that will act together," he told journalists Friday in Manila, Philippines.

Public opinion

Skeptics of military action have pointed at the decision to use force in Iraq, when the United States government under Bush marched to war based on a thin claim that dictator Saddam Hussein was harboring weapons of mass destruction.

Opponents are conjuring up a possible repeat of that scenario in Syria, though the intelligence being gathered on the use of WMDs in Syria may be more sound.

An NBC News poll conducted Wednesday and Thursday indicated that 50% of the public says the United States should not take military action against Damascus in response to the Syrian government's alleged use of chemical weapons against its own citizens, with 42% saying military action would be appropriate.

But the survey suggested that if military action would be confined to air strikes using cruise missiles, support rises.

More than 160 legislators, including 63 of Obama's fellow Democrats, signed letters calling for either a vote or at least a "full debate" before any U.S. action.