The US has struck an airbase in Syria's central region and caused losses, a military source said on Friday.
The Thursday night attack targeted the Shairat military base in the central Homs province, the source told Xinhua news agency.
The state TV called the attack an "American aggression".
The US launched 59 Tomahawk cruise missiles at the airbase from which the aircraft that carried out the chemical strikes earlier this week took off, CNN said.
The extent of losses remained unknown, the source said, adding that the army's general command is awaiting reports from Homs.
The strike marked the US response to the chemical attack on rebel-held town of Khan Sheikhoun in Idlib province, reports said.
Washington has accused the Syrian Army of being behind the toxic attack that killed over 70 including many children, an allegation totally denied by Damascus.