Russia has reacted angrily after the US launched a missile strike on a Syrian government air base.
US officials said the base had been used to launch a chemical weapons attack in north-western Syria that left dozens of civilians dead on Tuesday.
But Russia, which backs President Bashar al-Assad, condemned the US strike and suspended a deal designed to avoid mid-air collisions over Syria.
It is the first direct US military action against Syria’s government.
At least six people are reported to have been killed.
It comes just days after some 80 civilians, including many children, died in the suspected nerve gas attack in the rebel-held town of Khan Sheikhoun in Idlib province.
The Syrian opposition and Western powers say the Syrian government launched the attack but Syria denies this.
On the orders of President Donald Trump, two US Navy destroyers in the Mediterranean Sea fired 59 Tomahawk cruise missiles at Shayrat airfield in western Homs province at about 04:40 Syrian time (01:40 GMT).
They targeted aircraft, aircraft shelters, storage areas, ammunition supply bunkers and air defence systems at the Syrian government-controlled facility, according to the Pentagon.
It said the base was used to store chemical weapons and that “every precaution” had been taken to avoid casualties. The Russian military was informed beforehand, the Pentagon said.
Speaking from his Mar-a-Lago estate in Florida, Mr Trump said he had acted in America’s “vital national security interest” to prevent the use of chemical weapons.
Mr Trump branded President Assad a “dictator” who had “launched a horrible chemical weapons attack on innocent civilians” and called on “all civilised nations” to help end the conflict.
Source: BBC