Syrian warplanes targeted several residential districts of the northern city of Aleppo on Monday, killing at least five people including three children from one family, a rights watchdog said.
The five were killed and others were wounded in the central district of Maadi in the country's second city and commercial hub, a focal point for the fighting since mid-July, the Britain-based Syrian Observatory for Human Rights said.
"Three children from the same family were killed when their building collapsed in Maadi district, which is located in the Old City of Aleppo, 600 metres (yards) from the citadel," the watchdog's Rami Abdel Rahman told AFP.
"There are still people buried under the rubble," he added.
Videos posted to YouTube by activists, which AFP was unable to authenticate immediately, showed a mountain of rubble and men trying to clear away slabs of debris to free trapped residents.
Battles raged overnight in Aleppo's western districts of Jamiliyeh, Bustan al-Qasr, Furqan and in Zabdiyeh, while the army shelled rebel positions in Marjeh, Tariq al-Bab and Zabdiyeh, the Observatory said.
An AFP correspondent reported fighting in the southwest of the city until 4:00 AM (01H00 GMT) where rebels entrenched in Bustan al-Qasr and Bustan al-Zahraa exchanged fire with government troops in Ismailiyeh and Kamiliyeh.
Outside the northern metropolis, fierce clashes broke out between the army and rebels overnight near a military headquarters in western Aleppo province, the Observatory said.
In the capital, pre-dawn battles erupted in the eastern neighbourhood of Qaboon, said the watchdog, which gathers its information from a network of activists and medical sources on the ground.
Northwest of Damascus, a large explosion rocked Qudsaya suburb after midnight, and plumes of smoke were seen rising from the area.The northeast suburb of Douma and farmland between Douma and nearby Harasta were also shelled overnight, and casualties were reported when the town of Yarmud was bombarded, the Observatory said.
The army also shelled towns and villages across the northwest province of Idlib, while in the eastern city of Deir Ezzor, fierce clashes broke out between the army and rebels. There was no immediate information on casualties there.
Monday's violence came after at least 82 people -- 40 civilians, 16 rebels and 26 soldiers -- were killed nationwide on Sunday, the Observatory said.