Separately, at least 18 people were killed in government airstrikes in the northern city of Aleppo
Islamic State claims it has shot down a Syrian warplane and captured the pilot.
Footage put out by the IS-affiliated news agency Aamaq showed what the group said was wreckage of a MIG-23 jet.
IS said it had been shot down by anti-aircraft weapons near Mount Dakwah, southeast of Damascus.
Militants captured the pilot after he successfully bailed out, the group claimed.
The video starts with a black panel reading in English: "Wreckage of the Warplane Shot down by Islamic State Fighters East of Mt Dakwah in the Eastern Countryside of Damascus."
It then features several shots showing smoking wreckage of the plane including a wing, the engine and the painted Syrian flag on its tail wing.
Several fighters wearing camouflage outfits are also seen walking around.
AP Television said it could not independently verify the date and authenticity of the video.
Aamaq later identified the pilot as Azzam Eid.
The Syrian government has yet to comment on the downing of the plane.
Meanwhile, at least 18 people were killed in government airstrikes in the northern city of Aleppo, according to anti-regime activists.
A ceasefire called in February is close to falling apart amid rising violence and UN-brokered talks to resolve the conflict have become bogged down, with the Saudi-backed opposition delegation recently suspending its participation.
The High Negotiations Committee, which represents most of the opposition at the talks, accuses the government of repeatedly violating the ceasefire, illegally detaining thousands of people and blocking humanitarian aid access.
Islamic State and other jihadists are not represented in Geneva.