BEIRUT (AP) — 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 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.

In the capital Damascus, Syrian troops managed to capture more areas from the Islamic State group on the southern edge of the city cutting the region held by extremists into two parts.

The government-controlled Syrian Central Military Media said troops Thursday cut off IS fighters based in the Palestinian refugee camp of Yarmouk from those in the Hajar al-Aswad neighborhood to the south.

Yarmouk and Hajar al-Aswad are the last two areas outside government control in Damascus.

Syrian troops began a major offensive two weeks ago to retake the area under the cover of airstrikes. The fighting led to the displacement of thousands of Palestinian refugees and others to neighboring areas.

The Britain-based Syrian Observatory for Human Rights said that since the government offensive began on April 19, 112 soldiers and pro-government gunmen as well as 91 IS fighters have been killed. Dozens of civilians have been killed as well in the fighting, according to the war monitor.

Near Hajar al-Aswad, 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 Observatory 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 Daraa, which borders Jordan.