The Syrian army has shelled rebel-held districts of the commercial capital Aleppo as fighting flared anew around a southwestern neighbourhood that rebel fighters had quit last week.
The Shaar, Tariq al-Bab, Sakhur, Hanano and Bustan al-Qasr neighbourhoods all came under bombardment on Sunday, as troops pressed a ground offensive they had begun on Wednesday, the Syrian Observatory for Human Rights said.
An army colonel was killed in an assault by rebels in the Safira district, the Britain-based watchdog group said.
Gunfire was reported in the Qadam neighbourhood of the Syrian capital Damascus.
Heavy explosions were heard in the suburb of Harasta, the observatory said.
Elsewhere in the province, machine gun fire was heard in the town of Al-Tal, where 15 civilians were killed in shelling and clashes on Saturday as troops tried to regain control from rebels.
They were among 148 people killed across Syria on Saturday - 85 civilians, 20 rebels and 43 soldiers - the observatory said.