WASHINGTON — The Obama administration's move to punish Syria's government for allegedly using chemical weapons in a deadly attack last week appeared to suffer a setback Wednesday when the U.S. failed to get United Nations approval for use of force and British support was thrown into question.
The collapse of diplomatic efforts aimed at securing a U.N. Security Council resolution condemning Syria was expected. The British impediment was not.
The developments came as President Obama warned in a TV interview that chemical weapons "that can have devastating effects could be directed at us" and made clear he is considering limited military action against Syrian President Bashar Assad's forces.
"I have no interest in any kind of open-ended conflict in Syria," Obama said on "PBS NewsHour." "But we do have to make sure that when countries break international norms on weapons like chemical weapons that could threaten us, that they are held accountable."
How soon such strikes might occur remained unclear after British Prime Minister David Cameron, who has repeatedly called for strong action on Syria, was unable to muster enough support from lawmakers to push ahead with a vote to approve military intervention. Members of Parliament from both his Conservative Party and the opposition Labor Party insisted that a vote be delayed until U.N. chemical experts now in Syria issue a report.
U.N. Secretary-General Ban Ki-moon said the team needed four days to complete its work. "It is essential to establish the facts," he said. "The team needs time to do its job."
On Wednesday, the team visited the eastern Ghouta region northeast of Damascus, the zone that apparently was hit hardest by poison gas before dawn on Aug. 21. Assad's government is suspected of carrying out the attack, which killed hundreds.
U.S. officials, who have said there is already conclusive proof of Syrian government culpability, sought to avoid extending the investigation as a delaying tactic.
Marie Harf, a State Department spokeswoman, said the administration would not allow Syria to "hide behind a U.N. investigation into the use of chemical weapons to prevent any response from the United States."
In London, Parliament will consider a weaker-than-expected motion Thursday that deplores the use of chemical weapons and says that a humanitarian response might require "military action that is legal, proportionate and focused on saving lives by preventing and deterring further use of Syria's chemical weapons."
It will also say that "every effort" should be made to win a U.N. blessing for any military response. Russia, which is Assad's primary international supporter, made it clear Wednesday that it would not support any Security Council move to censure Syria or sanction military action.
At the U.N., in a meeting of the five permanent members of the Security Council, British representatives had proposed a resolution condemning Syria's use of banned chemical agents and called for "all necessary measures" to respond to it.
But Russia killed the proposal and foreclosed any further discussion, diplomats said.
Harf said U.S. officials would consult other countries about possible military action as well as other options, and "will take appropriate actions to respond in the days ahead."
After a meeting of the group's policymaking arm, NATO Secretary-General Anders Fogh Rasmussen said in Brussels that the suspected use of poison gas "cannot go unanswered. Those responsible must be held accountable."
His statement didn't commit NATO to joining a military operation but gave its blessing if one is launched, said Jorge Benitez, an analyst with the Atlantic Council of the United States and editor of the NATOsource blog. "They're saying, 'We support what you're going to do.' "
NATO members signaled fewer misgivings than before other recent U.S.-led interventions. Germany and Poland, which did not support the NATO-led air campaign against Moammar Kadafi's forces in Libya in 2011, supported the NATO statement on Syria, for example.
The United States appears likely to have support from France, Britain, Turkey and at least four Persian Gulf states. The Arab League voted Tuesday to condemn Syria's apparent poison gas use but stopped short of supporting military action.
The U.N. special envoy to Syria, Lakhdar Brahimi, told reporters in Geneva that an armed response without U.N. approval would be illegal under international law. He also said the Obama administration had not shared its evidence on the Assad government's alleged role in the attack.
"We will be very, very, very interested to hear from them what this evidence they have is," Brahimi said.
U.S. officials are expected to release an intelligence report as early as Thursday that they believe shows Syrian commanders ordered the use of chemical weapons.
On Capitol Hill, House Speaker John A. Boehner (R-Ohio) said the White House's outreach to Congress "has, to date, not reached the level of substantive consultation." His office sent the administration a list of questions about potential U.S. entanglement in Syria, including whether Congress would be asked to appropriate more money should a military operation drag on.
Boehner urged Obama to "personally make the case to the American people and Congress for how potential military action will secure American national security interests, preserve America's credibility, deter the future use of chemical weapons and, critically, be a part of our broader policy and strategy."
Assad's government has denied responsibility for the attack, blaming rebels who have fought to oust him from power since early 2011.
Richter reported from Washington and Chu from London. Staff writers Patrick J. McDonnell in Beirut and Christi Parsons in Washington contributed to this report.