'Aleppo civilians subject to war crimes on a daily basis' - Amnesty International

At least 10 people, including four children and teacher, were killed on Sunday when a barrel bomb hit a nursery school in the Seif al-Dawla district.

Civilians in Syria's second city of Aleppo are suffering unthinkable atrocities, Amnesty International said in a report.

The report alleges that government forces and many rebel groups are committing war crimes on a daily basis. The government has reportedly stepped up its bombardment of Aleppo in recent weeks in response to a rebel offensive.

President Bashar al-Assad categorically denied that barrel bombs had ever been used by his forces in a February interview.

At least 10 people, including four children and teacher, were killed on Sunday when a barrel bomb hit a nursery school in the Seif al-Dawla district.

Amnesty's report says that from January 2014 to March 2015, government aircraft launched continual attacks using barrel bombs - oil barrels, fuel tanks or gas cylinders packed with explosives, fuel, and metal fragments - in Aleppo.

Their targets included at least 14 public markets, 12 transportation hubs, 23 mosques, 17 hospitals and medical centres, and three schools.

The vast majority of fatalities from the eight attacks Amnesty investigated were civilians. According to the Violations Documentation Center, an activist-run monitoring group, barrel bombings killed at least 3,124 civilians and 35 rebel fighters in Aleppo province over the same period.

Amnesty said evidence suggested the air campaign in Aleppo had "deliberately targeted civilians and civilian objects", and noted that it was a war crime to intentionally make those not directly participating in hostilities the target of attacks.

Armed opposition groups in Aleppo were also accused of committing war crimes by using imprecise weapons such as mortars and improvised rockets fitted with gas canisters called "hell cannons" in attacks that killed at least 600 civilians in 2014.

The report also documented widespread torture, arbitrary detention and abduction of civilians by both government security personnel and rebels in Aleppo.