The Syrian government has moved most of its combat planes to Russian military bases in anticipation of further US strikes, American officials have said.

The relocation of its warplanes to Hmeimim air base and the adjacent Bassel al-Assad International Airport began shortly after the US's April 6 Tomahawk cruise missile strike on Shayrat airfield, which were carried out in retaliation for a chemical weapons attack that was believed to have been launched from that airfield.

The strikes were reported to have destroyed 24 aircraft, but planes continued to fly bombing raids out of the airfield just hours later.