The US has not ruled out limited strikes on Syrian government targets
The US has said it will act in its "best interests" in dealing with the Syria crisis, after British MPs rejected military intervention.
"Countries who violate international norms regarding chemical weapons need to be held accountable," the US said.
Washington accuses Syrian government forces of using chemical weapons - a claim denied by Damascus.
The move by British MPs, meanwhile, ruled out London's involvement in any US-led strikes against Syria.
Despite the unexpected outcome in the parliament of Washington's key ally, US Defence Secretary Chuck Hagel said America would continue to seek out an "international coalition" willing to act together on the Syrian crisis.
In a statement on Thursday, the White House said President Barack Obama's decision-making "will be guided by what is in the best interests of the United States".
It stressed that the president "believes that there are core interests at stake for the United States".
And in an intelligence briefing to senior members of Congress on the case for launching military action against Syrian President Bashar al-Assad's troops, State Secretary John Kerry said Washington could not be held to the foreign policy of others.
Eliot Engel, the top Democratic member on the House Foreign Affairs Committee, told reporters after the briefing that other Obama administration officials had said that it was "beyond a doubt that chemical weapons were used, and used intentionally by the Assad regime".
Mr Engel added that officials had cited evidence including "intercepted communications from high-level Syrian officials".
One of the Syrian officials overheard seemed to suggest the chemical weapons attack was more devastating than was intended, officials were quoted as saying by the New York Times.
At least 355 people are reported to have died in a suspected chemical attack in the Ghouta area - on the outskirts of the capital, Damascus - on 21 August.
UN weapons inspectors are currently in Syria investigating the allegations of the attack, which Damascus blames on rebel forces.
Samples taken during their site visits will be tested in various European laboratories to see whether an attack took place and what form it took, but the inspectors' mandate does not involve apportioning blame for the attacks.
The experts are due to finish their work later on Friday and give their preliminary findings to UN Secretary General Ban Ki-moon at the weekend.
In Thursday's statement, the White House also stressed that it would "continue to consult" with the UK over Syria, describing London as "one of our closest allies and friends".
The statement came after British members of parliament rejected the principle of military action against Damascus in a 285-272 vote.
Shortly after the surprise result, British Defence Secretary Philip Hammond confirmed to the BBC's Newsnight programme that Britain would not be involved in any military action.
But he said he expected "that the US and other countries will continue to look at responses to the chemical attack".
"They will be disappointed that Britain will not be involved. I don't expect that the lack of British participation will stop any action."
The vote in London is likely to send shock waves through the Obama administration, the BBC's North America editor Mark Mardell says.
He adds that Britain has tended to march alongside the US, and that this rejection of President Obama's argument will leave the administration bruised.
The defeat of the government motion also comes as a potential blow to the authority of British Prime Minister David Cameron, who had already watered down his proposal in response to the opposition's objections, correspondents say.
Earlier on Thursday, the five permanent UN Security Council members held a short meeting, but diplomats said their views remained "far apart".
One diplomat told the BBC that there had been "no meeting of minds", with Russia and China on one side, and the US, UK and France on the other.
Moscow, which has twice blocked resolutions condemning Mr Assad, called the meeting.
Analysts say Moscow is unlikely to agree to any resolution approving the use of force in Syria.
Russia has close ties with the Assad government, supplying its armed forces with weapons and housing its warships in Syria's ports.
More than 100,000 people are estimated to have died since the conflict erupted in Syria in March 2011, and the conflict has produced at least 1.7 million refugees.