Rebels shot down a Syrian regime helicopter Friday in a southwestern region near the borders with Israel and Lebanon, the Syrian Observatory for Human Rights monitor said.
"Rebel groups shot down a regime helicopter with a guided missile near the border with Lebanon and the occupied Golan," the Britain-based monitoring group's chief Rami Abdel Rahman said.
The size of the crew and its fate remained unclear, he said.
The area where the helicopter went down is an enclave controlled by Islamist rebel and jihadist groups and surrounded by regime forces.
Abdel Rahman said the fighting has increased there since October.
More than 340,000 people are estimated to have been killed in the Syrian war, which began in 2011 as the regime brutally crushed anti-government protests. Millions have been displaced.