Ministers agreed it was "highly likely" the Bashar-al Assad regime in Syria was responsible for a suspected chemical attack at a cabinet meeting on Thursday, BBC reported.
They agreed that the use of chemical weapons must not "go unchallenged".
But Transport Minister Jo Johnson later stressed: "There has been no decision to take military action at this point."
No details of UK involvement in any military action in Syria were mentioned in the Downing Street statement.
And Johnson, who was a guest on BBC One's Question Time, said: "I have to stress that no decision has been taken as to the nature of any action."
Medical sources say dozens of people were killed, including children, during the alleged toxic bombing of the formerly rebel-held town of Douma, in the Eastern Ghouta region.
US President Donald Trump spoke to Prime Minister May on Thursday evening, and both agreed that President Assad had "established a pattern of dangerous behaviour in relation to the use of chemical weapons".
A statement from Downing Street added: "They agreed to keep working closely together on the international response."
Trump is also expected to speak to French President Emmanuel Macron about what form action could take, with the White House saying "no final decision has been made".
Informed sources said May is prepared to take action against the Assad regime without first seeking Parliamentary consent.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
