Syrian soldiers are seen in the largely destroyed Hajar al-Aswad district, south of Damascus, Syria, on May 22, 2018. (Xinhua/Ammar Safarjalani)

MOSCOW, June 25 (Xinhua) -- Syrian government troops and the Free Syrian Army, supported by the Russian Air Force, repelled an attack by the Nusra Front in Syria's southern de-escalation zone, killing 70 militants, the Russian Defense Ministry said Monday.

The militants "lost three armored vehicles, 14 pickups with mounted machine guns and up to 70 people," the ministry said in a press release, adding that there were no deaths on the Syrian side.

The Free Syrian Army, an informal opposition group, has recently joined the government troops in the fight against the Nusra Front, an offshoot of al-Qaeda.

Under an agreement also involving Jordan, the United States and Russia last year, a temporary de-escalation zone was established in southern Syria to help restore stability and allow the delivery of humanitarian aid.