May has spoken with U.S. President Donald Trump repeatedly in recent days about what she says is the need to "uphold the worldwide prohibition on the use of chemical weapons". "The situation in Syria is horrific, the use of chemical weapons is something the world has to prevent", Brexit minister David Davis said on Thursday morning.
But his tweet Thursday said he "Never said when an attack on Syria would take place".
The US President tweeted that the air strikes would be coming "nice and new and smart". "Where is our 'Thank you America?'" he added.
US officials are confident the Syrian government was behind the attack in Douma over the weekend that left dozens of people dead, MSNBC reported. However, the exact number of people affected by the attack is unknown, with conflicting figures emerging from local reports.
Several countries led by the US are weighing military strikes in response to the Assad regime's chemical attack that killed dozens of people and affected 500 others in the Syrian town of Douma, in the Damascus suburb of eastern Ghouta.
Meanwhile, CIA Director Mike Pompeo said during his confirmation hearing to become secretary of state that "a couple hundred Russians" were recently killed in Syria, an apparent reference to a shootout involving US forces.
Defense Secretary Jim Mattis on April 12 said he personally believed an "inexcusable" use of chemical weapons had taken place in Syria.
For days, Trump has been sharpening his rhetoric against Syria and its backers, Russian Federation and Iran, calling Assad an "animal" on Sunday. But concrete evidence linking the Syrian regime to the attack might not be a prerequisite for a military response from the West.
Sources had indicated earlier in the day that the council would meet Thursday afternoon to make decisions regarding Syria.
Macron kept up the drumbeat for likely war with his claim of evidence that chemical weapons were used in the attack, although he did not elaborate.
Asked if he was referring to war between the U.S. and Russian Federation, he said: "We can not exclude any possibilities unfortunately because we saw the messages that were coming from Washington".
A joint military operation, possibly with France rather than the U.S.in the lead, could send a message of global unity about enforcing the prohibitions on chemical weapons and counter Syria's political and military support from Russian Federation and Iran.
Emmanuel Macron said France has proof the Syrian government carried out the attack, which aid groups have said killed dozens of people, and will decide whether to strike back when all the necessary information has been gathered.