At Moscow's initiative "the regime of silence in the province of Latakia and in the city of Aleppo has been extended from 00:01 (local time) on May 7 for 72 hours," the defence ministry said in a statement yesterday.
The truce had been due to end early today after giving residents some respite from two weeks of fighting that killed more than 280 civilians, even as clashes raged south of the city.
Russia has been flying a bombing campaign in Syria since September to back up the forces of its ally President Bashar Al-Assad.
Together with the United States, Moscow has been spearheading the latest diplomatic push to resolve the protracted conflict in the country.