The rights watchdog says it has collected eyewitness testimony and videos which suggest that at least 83 civilians – including 30 children – were killed in the Sheikh Maqsoud neighborhood of Aleppo, a city split between government and rebel control. The killings reportedly took place between February and April.

“Armed groups surrounding the Sheikh Maqsoud district…have repeatedly carried out indiscriminate attacks that have struck civilian homes, streets, markets and mosques, killing and injuring civilians and displaying a shameful disregard for human life,” Amnesty said in a Friday statement.

The organization’s deputy Middle East director, Magdalena Mughrabi, said the attacks “may amount to war crimes,” Reuters reported.

“By firing imprecise explosive weapons into civilian neighborhoods the armed groups attacking Sheikh Maqsoud are flagrantly flouting the principle of distinction between civilian and military targets, a cardinal rule of international humanitarian law,” Mughrabi said.

The violence is part of intense fighting in the region between the Kurdish YPG militia – which is backed by the US in the fight against Islamic State (IS, formerly ISIS/ISIL) – and rebel groups, some of which are backed by foreign countries via Turkey.

The YPG and its allies have been battling insurgents, including some Islamist groups, in the northern Aleppo province for several months. Shellings of Sheikh Maqsoud, which has a large Kurdish population, have intensified since February.

Both sides have accused the other of killing civilians.

Rebels claim the YPG wants to take control of a road which provides access from Turkey to Aleppo’s rebel-held areas. They also say the YPG is working in cahoots with the Syrian government – a claim which the YPG denies.

The YPG currently holds and uninterrupted 400km (250 mile) stretch of territory along the Syria-Turkey border. Turkey, which is fighting Kurdish militants in a controversial operation in the country’s southeast, views any YPG expansion with concern.

But despite any disapproval from Turkey, the YPG has been praised for its efforts against IS militants in Syria. The militia has been the most effective partner on the ground in the US-led campaign against IS, seizing large areas from the group last year.