In a statement, a Downing Street spokeswoman said: “The Prime Minister spoke to President Trump about Syria this evening.
“They agreed that the Assad regime had established a pattern of dangerous behaviour in relation to the use of chemical weapons.
“They agreed it was vital that the use of chemical weapons did not go unchallenged, and on the need to deter the further use of chemical weapons by the Assad regime.
“They agreed to keep working closely together on the international response.”
Jeremy Corbyn condemns Donald Trump’s rhetoric on Syria: ‘More war will not save life’
The Labour leader, Jeremy Corbyn, accused the government of “waiting for instructions” from the United States and said military intervention risks “escalating an already devastating conflict”.
Mr Corbyn said: “Further UK military intervention in Syria’s appalling multi-sided war risks escalating an already devastating conflict.
“The Government appears to be waiting for instructions from President Donald Trump on how to proceed. But the US administration is giving alarmingly contradictory signals.
The guided-missile destroyer USS Donald Cook is reportedly sailing towards Syria. The Arleigh Burke-class warship carries on board some 60 Tomahawk cruise missiles (EPA)
“Even US defence secretary James Mattis has said we ‘don’t have evidence’ and warned further military action could ‘escalate out of control’.”
Mr Mattis has warned an attack carried the risk of spinning out of control, suggesting caution ahead of a decision on how to respond to the situation.
The White House has said it was still assessing the evidence surrounding the suspected chemical weapons attack after its security council meeting on Thursday.
However, although Mr Mattis noted military action carried risks, he also emphasised the use of chemical weapons by Syria should not be tolerated.
The US, France and Britain have been in extensive consultations about launching a military strike as early as the end of this week.
France’s president, Emmanuel Macron, said they had “proof” the Syrian regime launched chlorine gas attacks and said his country would not tolerate “regimes that think everything is permitted.”
Emmanual Macron says France has proof the Bashar al-Assad used chemical weapons in Syria
The No 10 statement issued following the Cabinet meeting said Ms May had again described the attack on Douma as a “shocking and barbaric act” which represented a further erosion of international law.
“Cabinet agreed that the Assad regime has a track record of the use of chemical weapons and it is highly likely that the regime is responsible for Saturday’s attack,” it said.
“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.
“Cabinet agreed on the need to take action to alleviate humanitarian distress and to deter the further use of chemical weapons by the Assad regime.”
The statement made no reference to whether Parliament would be given a say on military action – prompting renewed concerns among opposition parties and some Tory MPs Ms May is prepared to go ahead without a Commons vote.
Mr Corbyn insisted MPs were entitled to a vote, saying Parliament “must be consulted”.
A medical worker giving a toddler oxygen through respirators following a suspected poison gas attack in the opposition-held town of Douma (Syrian Civil Defence White Helmets via AP)
Meanwhile, Labour’s shadow international development secretary unexpectedly backed intervention and suggested Mr Corbyn should stop making statements on foreign policy and instead leave the job to his shadow ministers.