The permanent members of the United Nations Security Council made no comment after meeting to discuss a British resolution calling for international military action in Syria after an alleged chemical weapons attack.
Envoys from the United States, Britain, France, Russia and China gathered on Thursday afternoon at UN headquarters in New York. The meeting was called by the Russian delegation, and ended with no statement from the participants.
A similar meeting on Wednesday ended after more than an hour with no agreement.
There were signs, however, that a coalition of Western countries, including the United States, France and the UK, are nonetheless moving towards military action against Syria after the alleged attack, which killed hundreds of people in Damascus suburbs last week.
Britain's government has published internal legal advice which it said showed it is legally entitled to take military action against Syria, even if the Security Council blocks such action.
"If action in the Security Council is blocked, the UK would still be permitted under international law to take exceptional measures in order to alleviate the scale of the overwhelming humanitarian catastrophe in Syria," a copy of the British government's legal position read.
It was "highly likely" that the Syrian government was behind the attack, the document said.
The UK and US have both already dispatched planes and warships to the eastern Mediterranean.
In a debate on Thursday, however, Prime Minister David Cameron told the British parliament it was "unthinkable" that Britain would launch military action against Syria if there was strong opposition at the Security Council.
A team of weapons inspectors, currently in Damascus, has yet to finish collecting samples and report their findings. The team is scheduled to leave on Saturday morning, and a UN spokesman has said their final report would take "more than days" to prepare.
Earlier on Thursday, Syrian President Bashar al-Assad said that his country would defend itself against any foreign military intervention.
"Syria will defend itself in the face of any aggression, and threats will only increase its commitment to its principles and its independence," the embattled Syrian leader told a visiting delegation of Yemeni politicians, according to state media.
The White House said on Thursday that it had strong circumstantial evidence linking Assad's government to an alleged chemical weapons attack in the East Ghouta suburbs of Damascus last week, which aid agencies say killed at least 355 people, and injured as many as 3,000 others.
The Syrian army "has been engaged in a military campaign targeting the areas where these attacks occurred," said Josh Earnest, a White House spokesman. But he did not cite any direct evidence showing that Assad or his top lieutenants ordered the attack.
The Syrian government has strongly denied accusations that it was involved.
The most likely option for an attack, US officials say, would be to launch cruise missiles from US ships in the Mediterranean in a campaign that would last several days.
Russia, a close ally of Syria and a permanent member of the Security Council, objects to international intervention. Foreign Minister Sergei Lavrov said on Wednesday that foreign military intervention would lead to "destabilisation of [...] the country and the region".
Chinese state media on Thursday said that any military intervention "would have dire consequences for regional security and violate the norms governing international relations".
More than 100,000 people have died in the Syrian conflict, which began more than two years ago, according to the UN and the opposition.