The UK-based Syrian Observatory for Human Rights (SOHR) said on Friday that Syrian regime forces killed at least five civilians in air strikes on an opposition-held neighbourhood of Aleppo city, al Saliheen, which it described as a “serious violation”.
"At least five civilians were killed in Syrian air force raids on the Salhin neighbourhood," SOHR director Rami Abdel Rahman said.
The raids follow a lull in strikes brought about by an unprecedented ceasefire that has largely held since coming into force on February 27.
"Friday's toll is the highest in Aleppo city since the ceasefire came into force and it is the most serious violation in the city since the truce came into effect," Abdel Rahman added.
Abdel Rahman also said that 10 people were also injured in the air strikes but warned that the death toll was likely to rise as there were people trapped under the rubble.
A reporter in the city said that the raids struck a mosque in al Saliheen.
On Thursday, a child was killed in regime bombardment of the opposition-held neighbourhood of Myassar, also in Aleppo city, the SOHR reported.
A fragile cessation of hostilities agreement brokered by the US and Russia has been in effect in Syria since Feb. 27.
The civil war in Syria involves five main factions - the regime, the opposition, Al Qaeda affiliate Nusra Front, DAESH, and the YPG.
According to a report released on Feb. 22, the SOHR estimated the overall death toll of the war to be nearly 370,000 people.
On the other hand, a report released by the Syrian Center for Policy Research on Feb. 11 puts the total death toll at 470,000, with around 1.9 million Syrians having suffered injuries at some point during the war.