Russian Federation saidreports of chemical weapons attacks were untrue and "bogus", despite monitoring watch groups describing the horror on the ground - including children and adults foaming at the mouth. Syrian activists, rescuers and medics said the attack in Douma killed at least 40 people, with families found suffocated in their houses and shelters.
One official said the U.S., France and Britain were considering military options that would be more extensive than the punitive, one-day strike last April.
On Wednesday evening, Russian Federation used its veto at the United Nations for the second time this week, to stop an global investigation into chemical weapons use in Syria.
"President Trump just finished a meeting with his national security team to discuss the situation in Syria".
Trump did not detail what a strike on Syria would look like, or whether these would be United States missiles.
The British government has signaled it is ready to back U.S. military action against Syria, saying it is "highly likely" the Assad regime used chemical weapons on its own people and that such action could not go unchallenged.
On Thursday US officials were quoted as saying that samples from victims have tested positive for chlorine and a nerve agent.
A special hotline for the USA and Russian militaries to communicate about operations in Syria is active and being used by both sides, Moscow said on April 12.
The White House said it was still assessing the evidence after its security council meeting on Thursday.
But the cabinet's call for "action" to prevent further use of chemical weapons included no details on the method or timing of such strikes, while leaving open the possibility of other responses. "Following a discussion in which every member present made a contribution, Cabinet agreed it was vital that the use of chemical weapons did not go unchallenged", the spokesperson added. The president previously struck Assad for using Sarin gas against civilians in April 2017 and is publicly incensed at the regime's repeated action.
Labour leader Jeremy Corbyn insisted that MPs were entitled to a vote, saying Parliament "must be consulted".
The emergency cabinet meeting, at 3.30pm London time, comes amid widespread calls by opposition leaders for MPs to be given a vote before taking any military action in Syria.
The Organization for the Prohibition of Chemical Weapons, an worldwide chemical weapons watchdog organization said Thursday that its team is en route to Syria and will begin work Saturday to investigate the attack.
The French president does not need parliamentary permission to launch a military operation.