Three Russian and several Turkish soldiers were injured Tuesday in Syria's volatile Idlib province when a joint military patrol hit an improvised explosive device, the Russian defence ministry said.

The device blew up at 8:50 local time (0550 GMT) as their convoy patrolled the M4 highway in the southern part of a de-escalation zone, a statement said.

A Russian and a Turkish armoured vehicle were damaged, with three Russians "lightly injured," it said. Several Turkish soldiers were also wounded.

Russia and Turkey launched the patrols along the M4 in March following a ceasefire agreement aimed at stopping heavy fighting in and around Idlib, the last major bastion of anti-government forces in Syria's civil war.

Russia backs Syrian President Bashar al-Assad in the conflict and Turkey backs the opposition, but the two countries have agreed several deals to reduce hostilities.