Syrian rebels have announced a big offensive aimed at breaking the government siege of rebel-held east Aleppo.
A UK-based monitoring group said rebels had fired "hundreds" of missiles into western Aleppo, killing at least 15 civilians.
They are also reported to have targeted al-Nayrab military airport to the east.
About 275,000 people have been besieged by pro-government forces since September.
Syria and its ally Russia have recently intensified air strikes on the east.
The attacks are so far coming from rebels outside Aleppo, but it is understood that rebels inside the city will join the offensive.
"All the revolutionary factions, without exception, are participating in the battle," the military spokesman for the Fastaqim faction inside the city said, AP news agency reported.
The UK-based Syrian Observatory for Human Rights (SOHR) said rebels had fired Grad missiles at al-Nayrab.
18.12°C Kathmandu
