Earlier, President Trump appeared to row back from a suggestion on Wednesday that missile strikes were imminent, insisting in his latest tweet that he had never set out a timetable for military action.
Earlier, Defense Secretary Jim Mattis said that the USA would not rule out military force against the Assad regime.
May said, “We can not allow the use of chemical weapons to become normalized”.
After mentioning the strike, Trump’s tweet said: “In any event, the United States, under my Administration, has done a great job of ridding the region of ISIS”.
Haley has been a vocal critic of Russia’s actions in Syria.
Speaking in the British city of Birmingham on Wednesday, May said “all the indications” are that the Syrian regime was responsible for a chemical weapons attack in Douma, adding that the use of such weapons “cannot go unchallenged”.
President Donald Trump says an attack on Syria could take place “very soon or not so soon at all!”
Still, despite Trump’s tweets early Wednesday that promised “nice and new and ‘smart!’” missiles were headed for Syria, Sanders said no “final decisions have not been made on that front”.
White House Press Secretary Sarah Sanders said on Friday that Syria was responsible for the attack but added pointedly, “We also hold Russian Federation responsible for their failure to stop chemical weapons attacks from taking place”.
“Russia vows to shoot down any and all missile fired at Syria”.
But relations have instead soured over mounting evidence of Russian meddling in the 2016 presidential election, Russia’s alleged poisoning of a former double agent in Britain and Putin’s support of Assad’s government in Syria.
State news agency RIA Novosti on Wednesday quoted Andrei Krasov, deputy chairman of the State Duma’s defense committee, as saying that Russian Federation will treat a U.S. airstrike on Syria “not just as an act of aggression but a war crime of the Western coalition”.
Trump said there was little question that Syria was responsible for the apparent weekend attack, although the government of President Bashar Assad denied it.
Meanwhile, Moscow said the formerly rebel-held district of Eastern Ghouta – including Douma, the target of Saturday’s attack – had been “totally stabilized” and would soon be patrolled by Russian military police.
The president made the statement in a tweet Thursday morning.
Nearly three-quarters of a million Syrians have been forced out of their homes by fighting in the first months of 2018, according to the senior United Nations official coordinating the crisis response.
This comes as Trump has also said that, “Our relationship with Russian Federation is worse now than it has ever been, and that includes the Cold War”.
Fielding questions at the White House, Trump press secretary Sarah Sanders said it would be “outrageous” to say that Trump’s recent announcement that he intends to remove all USA forces from Syria in the coming months had emboldened Assad.
At a Pentagon news conference alongside Mattis, and with British and French military officers beside them to emphasize allied unity, Gen. Joseph Dunford said the attacks targeted mainly three targets in western Syria.
A Downing Street spokesperson said Mrs May, Mr Trump and Mr Macron had agreed that “reports of a chemical weapons attack in Syria were utterly reprehensible”.
Following a sarin attack on Syrian civilians in the town of Khan Sheikhoun in April 2017, Trump ordered strikes on the Shayrat air base in Homs.
He warned that there had been an “escalation towards a significant crisis” in recent days.