Donald Trump has justified the US missile strike on Syrian air base in a short speech to the American people.

Speaking from his Mar a Lago resort in Florida where he was meeting Chinese Premier Xi Jinping, he said preventing and deterring the use of chemical weapons was in the "vital national security interest of the US".

Here is is speech in full:

"On Tuesday, Syria launched a horrific chemical attack on innocent civilians. Using a deadly nerve agent, Assad choked out the lives of hopeless men, women, and children.

It was a slow and brutal death for so many. Even beautiful babies were cruelly murdered in this very barbaric attack. No child of god should ever suffer such horror.

Tonight I ordered a targeted military strike on the air field in Syria from where the chemical attack was launched

It was in the vital national security interest of the US to prevent and deter the use of deadly chemical weapons.

There can be no dispute that Syria used banned chemical weapons, violated its obligations under the chimerical weapons convention and ignored the urging of the UN security council.

Years of previous attempts at changing Assad's behaviour have all failed and failed very dramatically.

As a result, the refugee crisis continues, and the region continues to destablise, threatening the US and its allies.

Tonight I call on all civilised nations in seeking to end the slaughter and bloodshed in Syria and also to end terrorism of all kinds and all types.

We ask for God's wisdom as we face the challenge of our very troubled world. We pray for the lives of the wounded and the souls of those who have passed.