"The silence regime, which was introducted on June 19 for 24 hours in Aleppo City, has been broken by Nusra Front massive artillery and mortar attacks on north-western, north-eastern, and southern suburbs of the city," Russia's defense ministry said in a statement.
The artillery was fired from El Khalid Sheikh Maqsood, Az Zagra, Al-Nayrab airport, and the nearby town of Handrat.
The cessation of hostilities was observed in most Syrian provinces, with five recorded violations in Damascus province.
The ceasefire was agreed to by 157 settlements in the region following negotiations.
During this time, humanitarian aid was delivered by the Russian military, and a convoy of 41 cargo vehicles delivered stores of cereals, flour, and medicine to Aleppo province.