Rockets have struck two eastern districts of Aleppo city, killing at least 12 people and trapping many families in the ruins of their homes, activists in the city said.
"There are families buried under the rubble," said an activist called Baraa al-Youssef, speaking by Skype after visiting the scene in his Ard al-Hamra neighbourhood.
"Nothing can describe it, it's a horrible sight."
Video footage posted by several activists showed a burning building and people carrying the wounded to cars to be ferried to hospital. It was hard to gauge the scale of the damage in the night-time footage but rubble was clearly visible on the ground.
Rami Abdulrahman of the British-based Syrian Observatory for Human Rights said three explosions shook the city and reported at least 12 people had been killed - a toll he said was likely to rise.
Youssef said 30 houses were destroyed by a single rocket.
On Tuesday activists said at least 20 people were killed when a large missile of the same type as Russian-made Scuds hit the rebel-held district of Jabal Badro.