President Trump said Thursday a decision on US action in Syria would come "very soon or not so soon", signaling a slowing of what had seemed a quick drive for airstrikes in retaliation for the suspected use of chemical weapons against Syrian civilians. Saudi Arabia said it would support a military operation in Syria.
Hours after the first missiles fell on Friday night, it was not yet clear how extensive the attacks were.
Analyst Hossein Sheikholeslam, a former Iranian ambassador to Damascus, told state television the attacks would help unite Syrians behind the government.
Trump said the operation would be conducted in cooperation with the militaries of France and Britain.
He said that while the coalition forces had many potential targets from which to choose, the three sites were chosen for there significance to Syria's chemical weapons program and well as their location and layout, in an attempt to minimize risk to innocent civilians.
The evil and the despicable attack left mothers and fathers, infants and children, thrashing in pain and gasping for air.
Defense Secretary James Mattis, new national security adviser John Bolton, Vice President Mike Pence and US ambassador to the United Nations Nikki Haley were all involved in the talks. He said that the "United States has a vital national interest in averting a worse catastrophe in Syria".
They agreed to "keep working closely" on the issue, Mrs May's office said in a statement.
"Tonight, I ask all Americans to say a prayer for our noble warriors and our allies as they carry out their missions", Trump said. "Right now we have no additional strikes planned", he said.
Mr. Trump described a very specific type of target that the US would go after, which are Syria's chemical weapon capabilities.
USA officials had earlier said that Trump had pressed for a more aggressive United States strike against Syria than his military chiefs had recommended.
Assad has a pattern of denying the use of banned weapons.
Part of the calculation this week has also been gaming out how Russian Federation will respond. The strike came as a direct response to the Khan Shaykhun chemical attack that occurred days before the missile strike.
Last week the President fired off a tweet telling Russian Federation to "Get ready" for missiles fired at Syria, saying they will be "coming, nice and new and 'smart!'". Analysts are puzzled by the logic of Trump's decision to stand up against "Gas Animal Assad" by raining explosives on Syria and killing Syrians.
Last April, US President Donald Trump fired 59 Tomahawk missiles at Al Shayrat airfield in Syria, in response to an alleged chemical attack in Idlib province. He stated, "We cannot purge the world of evil or act everywhere".
Trump is also offering prayers for the Middle East and for the United States. We have to make some further decisions. "But the fate of the region lies in the hands of its own people".
This post will be updated as more information is learned about Trump's announcement on Syria.
Britain has blamed Russian Federation for the poisoning - a charge vehemently denied by Moscow which has accused London of failing to come up with evidence for its claims.