UN personnel search for remains of mortar shells in the Israeli-annexed Golan Heights, on Oct. 21, 2017. Israel on Saturday attacked three Syrian army posts after errant projectiles hit the Israeli-annexedGolan Heights, in an escalation of the Israeli response to spillovers from its war-torn neighbor. (Xinhua Photo)

DAMASCUS, Dec. 1 (Xinhua) -- Syria's rebels downed a military helicopter near the Israeli-occupied Golan Heights on Friday, a monitor group reported.

The rebels fired a direct missile on the Syrian helicopter in an area near the Golan Heights and the Lebanese borders, said the Syrian Observatory for Human Rights.

The London-based watchdog said the fate of the crew members is still unknown, adding that the chopper crashed in the southwestern countryside of the capital Damascus.

The Syrian official media outlets have yet to comment on the report.

The watchdog, which says it relies on a network of activists on the ground, said the military operation is still going on in the southwestern countryside of Damascus between the Syrian army and rebels, including the al-Qaida-linked Nusra Front, also known as the Levant Liberating Committee.

The battles have been raging in the past 72 hours in the area, the watchdog added.

The Syrian army has repeatedly said the war on the terror groups will continue in Syria, particularly against the Nusra Front and Islamic State militants.