A Western-backed rebel group in Syria and a monitor of the conflict there said rebels fired anti-aircraft machine guns at a Syrian military jet on Tuesday, damaging the plane, about 80 km (50 miles) east of Damascus.
Western-backed rebels had also hit another Syrian military jet last month, causing it to crash.
It was not clear if the plane hit on Tuesday had crashed, said Saad al-Haj, spokesman for Jaish Osoud al-Sharqiya rebel group. "The men targeted the plane, they saw smoke coming out of it," he said. "It withdrew backwards toward the regime's areas."
There was no immediate comment from the Syrian military.
The Syrian Observatory for Human Rights, a Britain-based war monitoring group, said that the plane was damaged and was forced to come down in the al-Sin military air base in rural Damascus, but that it did not crash.
Ousoud al-Sharqiya is one of the main rebel groups operating in the sparsely populated, southeast Syrian desert known as the Badia, which stretches to the Iraqi and Jordanian borders.
A day earlier, Syrian troops and Iranian-backed militias launched an assault on Bedouin villages in the southeast to consolidate control of a swathe of desert stretching to the Iraqi border, Western-backed rebels said.
Tuesday's flare-up in the Badia was near the area where a U.S.-Russian brokered ceasefire came into effect this week in the southwest of Syria
