Donald Trump has announced he ordered a cruise missile strike on a Syrian air base from where the US believes this week's devastating alleged chemical attack on civilians was launched.
The US president said in a televised address there could be "no dispute" Bashar Assad was to blame for Tuesday's attack.
Here is Mr Trump's full statement:
"My fellow Americans, on Tuesday, Syrian President Bashar al-Assad launched a horrible chemical attack on innocent civilians using a deadly nerve agent. Assad choked out the lives of helpless men, women and children. It was a slow and brutal death for so many. Even beautiful babies were cruelly murdered at this very barbaric attack. No child of God should ever suffer such horror.
"Tonight, I ordered a targeted military strike on the airfield in Syria from where the chemical attack was launched. It is in this vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons. There can be no dispute that Syria used banned chemical weapons, violated its obligations under the Chemical Weapons Convention and ignored the urging of the UN Security Council.
"Numerous previous attempts at changing Assad’s behaviour have all failed and failed very dramatically. As a result, the refugee crisis continues to deepen and the region continues to destabilise, threatening the United States and its allies.
"Tonight I call on all civilised nations to join us in seeking to end the slaughter and bloodshed in Syrian and also to end terrorism of all kinds and all types. We asked for God’s wisdom as we face the challenge of our very troubled world. We pray for the lives of the wounded and for the souls of those who passed. And we hope as long as America stands for justice and peace and harmony will in the end prevail.
"Good night and God Bless America and the entire world."