The United States launched dozens of missiles against an airbase in western Syria in response to a chemical weapons attack that the US said was a deliberate act carried out by Syria earlier this week.
President Donald Trump said he ordered the missile attack to hit the airbase that Syrian government forces used to launch the deadly chemical weapons attack on Tuesday.
"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 United Nations Security Council," Trump said.
The move was in the "vital national security interest of the United States to prevent and deter the spread and use of deadly chemical weapons," he added.
The target of the attack was Shayrat Airfield in Homs governorate. More than 50 tomahawk missiles were launched from two US destroyers in the eastern Mediterranean Sea, the Pentagon said. The attack took place about 4:40 am Friday (1240 GMT).
Speaking at his resort in Mar-a-Lago, Florida, Trump called on "civilized nations" to "end the slaughter and bloodshed in Syria" after launching a missile strike at a Syrian government air base.
He said the nerve gas attack on Khan Sheikhoun, which killed more than 80 people, "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 in this very barbaric attack. No child of God should ever suffer such horror."
He said all attempts to change behaviour of Syrian President Bashar al-Assad "have failed and failed dramatically." As a result the refugee crisis continues and the region continues to destabilize.
Trump not only urged other countries to help end the war in Syria, but also "end terrorism of all kinds and all types."
The Syrian opposition said the missile strike was an important US reaction.
"This is a very important American reaction and let us say this should be the beginning to tell this (Syrian) regime that you cannot go by unpunished," Ahmed Ramadan, the head of the press department at the Syrian National Coalition (SNC) said.
US Senator Marco Rubio called it a significant step.
"There is a messaging component to this, but it is more than just a message," Rubio said on CNN. "It is a significant degrading of their capabilities in the air."
Earlier, Russia's deputy ambassador to the UN warned of "negative consequences" if the United States took military action against Syria after the chemical attack.
"First of all we have to think about negative consequences. Negative consequences," Vladimir Soronkov told reporters in response to questions about possible US air strikes.
"All responsibility if military action occurred, will be on shoulders of those who initiated such doubtful and tragic enterprise."