Defense hawks who have long called for action against Syria said the President was justified in striking Bashar Assad's government forces in Homs.

"Tonight I call on all civilised nations to join us in seeking to end this slaughter and bloodshed in Syria and also to end terrorism of all kinds and all types", he said.

Images of dead and suffering children following the chemical attack apparently changed Trump's mind about intervening more directly. The hotline's primary intent is to ensure Russian planes conducting combat missions in Syria's skies don't stumble into an accident or confrontation with aircraft flown by the USA -led coalition fighting an Islamic State insurgency in the north of the country. Interestingly, these are the same actions Trump never wanted his predecessor Barack Obama to take. Trump opted against congressional approval, though he had tweeted in 2013 that it would be a "big mistake" for then-President Obama if he did not pursue that course.

"Washington's step will inflict major damage on US-Russia ties".

And: "What I am saying is stay out of Syria".

"Does the Administration have contingency plans to deter or respond should Assad retaliate against US interests or allies in the region?"

He called on "all civilised nations" to help end the conflict in Syria. There is no upside and tremendous downside. European Union will work with the USA to end brutality in Syria. American-allied forces have gained ground against ISIS and now seem set not only to defeat ISIS in its "capital" city of Raqqa but also to dominate northern Syria going forward. "Why can't we just be quiet and, if we attack at all, catch them by surprise?"

It's not clear whether the attack on the air base was the first of a broader campaign against the Assad regime.

US President Donald Trump ordered a massive military strike on a Syrian air base, in retaliation for what he said was a "very barbaric attack" on Tuesday that is suspected to have contained a nerve agent.

The missiles struck their targets, which also included Syrian aircraft and fuel stations, at 4.40am local time on Friday.

The U.S. officials, however, said they were also reviewing evidence to see if Russian Federation was complicit in the attack on the northern Syrian town of Khan Sheikhoun, where more than 80 people were killed.

"It was a slow and brutal death for so many", Trump said of the Khan Sheikhoun atrocity. Even handsome babies were cruelly murdered at this very barbaric attack. "No child of God should ever suffer such horror", he said.

US Secretary of State Rex Tillerson said that the US strikes were "proportionate" and showed that President Trump was willing to act when other countries "cross the line".

It did, however, indicate how far Trump was willing to go, possibly with his domestic audience in mind, even if it risked contradicting previous positions as well as confrontation with Assad's other main military backer, Russia.

"Russian forces were notified in advance of the strike using the established deconfliction line", Pentagon spokesman Jeff Davis said in a statement Thursday.

Peskov defended Syria by stating that the Bashar al-Assad-led government in the nation has no chemical weapons and that their destruction has been monitored by worldwide observers.