"We're again confident that both Syria had responsibility in this chemical weapons attack, but we also hold Russian Federation responsible for their failure to stop chemical weapons attacks from taking place", said White House press secretary Sarah Sanders.
Syria was long known to have large chemical weapons stockpiles. Explosions lit up the skies over Damascus, the Syrian capital, as Trump spoke from the White House.
Syrian media reported that air defences hit 13 rockets south of Damascus. "This massacre was a significant escalation in a pattern of chemical weapons used by that very bad regime'" he said.
This is the first time as Prime Minister that I have had to take the decision to commit our armed forces in combat - and it is not a decision I have taken lightly.
The largest USA air and naval strike force since the 2003 Iraq war was said to be heading towards Syria, according to reports in The Times, paving the way for strikes within the next three days.
Syrian opposition leader Nasra al Hariri called for an end to what he described as all attacks against civilians by the Syrian regime and its allies, whether using chemical or conventional weapons.
There was no immediate word on any casualties or damage. The Pentagon said it would provide a more detailed assessment on Saturday morning.
Britain's defence ministry said "very careful scientific analysis" had been applied to maximise the destruction of stockpiled chemicals while minimising any risk of contamination to surrounding areas.
In that instance, 59 Tomahawk missiles were fired at a Syrian airbase in the western part of the country following a chemical attack blamed on Assad's forces.
Defense Secretary James Mattis appeared to have referenced Russian Federation and warned of its "disinformation campaign" in the coming days.
The U.S. strike comes nearly exactly a year after a previous U.S. strike, which was also in response to the Syrian regime's alleged use of chemical weapons.
Those targets were carefully selected to avoid collateral damage and the risk of hitting Russian or Iranian troops, an act that Dunford and other Pentagon officials anxious could draw the United States into a brutal face off with near-peer enemies, the general said.
The US has about 2,000 troops on the ground in Syria as advisers to a makeshift group of anti-Islamic State fighters known as the Syrian Democratic Forces.
Haley highlighted "He [President Trump] has said from the beginning we have to know we're right, we have to know all the information, we have to know there's proof and we have to know that we're taking every precaution necessary should we take action", she said.
He said: "In Syria, we need to demonstrate that we are willing to use force and that's what the President is doing". The United States will be a partner and a friend, but the fate of the region lies in the hands of its own people.
US military officials have said they believe the American forces should remain a while longer to help stabilize the places where ISIS was pushed out.
He called them "most responsible for supporting, equipping and financing the criminal Assad regimen".