(CNN) — A U.S. intelligence report assessed with “high confidence” that Syria’s government planned and launched last week’s chemical weapons attack that killed more than 1,400 people, Secretary of State John Kerry said Friday in releasing details intended to muster support at home and abroad for a military response.
Citing evidence including video footage of children and other victims lying dead with no visible wounds, Kerry said such “indiscriminate, inconceivable horror of chemical weapons” is what Syrian President Bashar al-Assad “did to his own people.”
Kerry’s statement and the release of the declassified intelligence report came as President Barack Obama’s administration faced rising resistance to a military strike against the Syrian regime in response to its use of banned chemical weapons.
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.
Other European allies support action against Syria but want the United Nations to lead the effort, something Kerry said would not happen because of opposition by permanent Security Council member Russia, a Syrian ally.
At home, questions about the veracity of the U.S. intelligence and whether Washington is headed for another war based on false information — like happened in Iraq — have emerged from both parties in Congress.
Kerry: “We will not repeat” Iraq
Kerry insisted Friday 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 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.”
In addition, “we know where the rockets were launched from, and at what time,” he said. “We know where they landed, and when. We know rockets came only from regime-controlled areas and went only to opposition-controlled or contested neighborhoods.”
Quoting from the U.S. assessment, Kerry said the attack killed 1,429 people, including more than 400 children.
“We assess with high confidence that the Syrian government carried out the chemical weapons attack against opposition elements in the Damascus suburbs,” he said.
Al-Assad’s government has claimed that jihadists fighting on the opposition’s side carried out the chemical weapons attacks on August 21 to turn global sentiments against it. Senior administration officials told reporters Friday there is no evidence to support that claim.
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.
Read the full assessment
Meanwhile, the U.N. mission investigating the suspected chemical weapons attack in Syria has completed its collection of samples, said Martin Nesirky, spokesman for the U.N. secretary-general.
Nesirky told reporters that inspectors visited a government military hospital in Damascus and the last of them will leave Syria on Saturday.
Even as the inspection was winding down, opposition activists said Friday there is evidence of another deadly chemical weapons attack in Syria. Seven people died and dozens were injured Monday in the attack on a school in northern Syria.
As the U.N. inspectors began leaving Syria on Friday, Obama met with his national security team amid continuing U.S. signals of a possible military attack.
A U.N. Security Council meeting on Syria ended in deadlock Thursday, and Secretary-General Ban Ki-moon met Friday with the panel’s five permanent members to try to find consensus. So far, opposition to any military response by Syrian ally Russia 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.
While noting that he and the nation are “tired of war,” Kerry said such fatigue “does not absolve us of our responsibility.”
“Just longing for peace does not necessarily bring it about, and history would judge us all extraordinarily harshly if we turned a blind eye to a dictator’s wanton use of weapons of mass destruction against all warnings, against all common understanding of decency,” he said.
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 Turkish Foreign Minister Ahmet Davutoglu. “From our perspective, there is no doubt that the regime is responsible.”
Iran: U.S. military action in Syria would spark ‘disaster’
Alone or together?
The White House has made clear that the United States will respond in some form to the Syrian use of banned chemical weapons, but said Obama is still deciding exactly what to do.
Previously, the White House 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.
However, the British Parliament’s 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.
French President Francois Hollande told Le Monde newspaper Friday that intervention should be limited and not be directed toward al-Assad’s overthrow, a position also expressed by Obama.
On Friday, former President George W. Bush said Obama’s “got a tough choice to make.”
“I was not a fan of Mr. Assad. He’s an ally of Iran, he’s made mischief,” Bush told Fox News on Friday. “If he (Obama) decides to use the military, he’s got the greatest military in the world backing him up.”
Also Friday, another Obama predecessor, 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.”
U.S. 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.
Chemical weapons in Syria: How did we get here?
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.
Supporters of a strong U.S. response say that no further proof is needed that the Syrian regime was responsible.
“Come on. Does anybody really believe that those aren’t chemical weapons — those bodies of those children stacked up?” Republican Sen. John McCain of Arizona said Thursday on CNN.
Read UK intelligence on chemical weapons
Democrats say Obama needs to make the case to Congress that al-Assad’s regime was responsible and that a possible intervention won’t get out of hand.
“The action has to have a very limited purpose, and the purpose is to deter future use of chemical weapons,” Democratic Rep. Chris Van Hollen of Maryland told CNN.
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.
The author of one of those letters, Democratic Rep. Barbara Lee of California, said Obama should seek “an affirmative decision of Congress” before committing American forces. Congress is in recess until September 9, though some members advocate returning early to debate the matter.
Map: U.S. and allied assets around Syria
Haunted by Iraq
Britain’s Joint Intelligence Committee has concluded it was “highly likely” that Syrian government forces used poison gas in the attack last week, according to a summary of the committee’s findings released Thursday. It said at least 350 people died.
Before military intervention got voted down, Prime Minister David Cameron had said his government would not act without first hearing from the U.N. inspectors and giving Parliament another chance to decide the matter. But his opposition seemed to be reminded of the Iraq war.
Opinion: For the U.S., Syria is a problem from hell
“I think today the House of Commons spoke for the British people who said they didn’t want a rush to war, and I was determined we learned the lessons of Iraq, and I’m glad we’ve made the prime minister see sense this evening,” Labour Party leader Ed Miliband told the Press Association.
Though Cameron did not need parliamentary approval to commit to an intervention, he felt it important “to act as a democrat, to act a different way to previous prime ministers and properly consult Parliament,” he said Friday.
UK Government’s legal position on Syrian regime’s chemical weapon use
He regrets not being able to build a consensus of lawmakers, he said.
Lack of support for military intervention at the United Nations was less of a surprise, due to Russia’s known opposition.
“Russia is against any resolution of the U.N. Security Council, which may contain an option for use of force,” Deputy Foreign Minister Gennady Gatilov said Friday.
The U.N. weapons inspectors expected to be out of Syria by Saturday will brief Ban, who then will swiftly brief the Security Council on the findings.
Why Russia, Iran and China are standing by al-Assad
–CNN’s Barbara Starr, Lesa Jansen, Ben Brumfield, Elise Labott, Christine Theodorou, Holly Yan, Nick Paton Walsh, Jim Acosta, Max Foster and Bharati Naik contributed to this report.