The US has carried out an air strike targeting Iran-backed militias in Syria, in the first military action undertaken by the Biden administration.

The Pentagon said the strike destroyed "multiple facilities" and was ordered in response to attacks against US and coalition personnel in Iraq.

Militia officials said one person had been killed but a war monitor reported at least 22 fatalities.

Syria condemned the attack as a "bad sign" from the new US administration.

The Pentagon said its strike near the Iraqi border in eastern Syria was a "proportionate military response" that was taken "together with diplomatic measures", including consulting coalition partners.

It came after a civilian contractor was killed in a rocket attack on US targets earlier this month. A US service member and five other contractors were also injured when the rockets hit sites in Irbil, including a base used by the US-led coalition. - AFP