(CNN) -- 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.
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.
"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.
