A Russian pilot was killed in Syria on Saturday after parachuting into rebel-held territory when his plane was shot down, the Russian defence ministry said.

“A Russian Su-25 aircraft crashed during a flight over the Idlib de-escalation zone. The pilot had enough time to announce he had ejected into the zone, under the control of al-Nusra Front fighters,” the ministry said, quoted by Russian press agencies.

“The pilot was killed in fighting against terrorists.” It added that “according to preliminary reports, the plane was shot down by a portable anti-aircraft missile system.”

The Russian army claimed it had killed “more than 30 al-Nusra Front fighters” during a strike with “high-precision weapons” in the area where the plane was shot down. The region where the plane crashed is controlled by Hayat Tahrir al-Sham, a militant outfit dominated by Al Qaeda's former Syrian affiliate.

Forces supporting president Bashar al-Assad's regime, backed by Russia, launched an offensive at the end of December to recapture the southeastern province of Idlib, the last enclave completely out of Damascus's control.

Opposition groups have in the past shot down Syrian planes, but rarely those of the Russian army. In August 2016, five Russian soldiers were killed after their helicopter was shot down by rebel groups in Idlib. In November 2015, Turkey shot down a Russian military aircraft, which caused a diplomatic crisis between Moscow and Ankara.