Moscow: A Russian fighter jet crashed Thursday off the coast of Syria, killing both pilots, according to Russia’s Defense Ministry, which said the plane did not come under fire and that the crash may have been caused by a bird getting sucked into one of the engines.

State news agency Tass cited the ministry as saying the Su-30 crashed shortly after takeoff from the Russian air base at Hemeimeem in Syria.

Russia has been waging an air campaign in support of President Bashar Al Assad’s forces since 2015.

In March, a Russian military cargo plane crashed as it was descending to land at Hemeimeem, killing all 39 people onboard.

The military blamed the crash on a technical error and insisted the plane was not shot down.

Russia leases the Hemeimeem military base in Syria, near the Mediterranean coast.

Near the capital, Damascus, preparations were underway to evacuate thousands of opposition fighters and civilians from three southern suburbs following a deal reached last week to hand over the area to government forces.

State TV said buses started entering the southern suburbs of Babila, Beit Sahem and Yalda to evacuate some 5,000 fighters and their families, while those who decide to stay are eligible for amnesty.

The Britain-based Syrian Observatory for Human Rights said some of the fighters and civilians will be heading to the northwestern rebel-held province of Idlib and the town of Afrin, which is controlled by Turkey-backed opposition fighters.

Others will head to rebel-held areas in the southern province of Dara’a, which borders Jordan.