Beirut: The death toll from an air strike by US-led forces on the northern Syrian province of Aleppo on Friday has risen to 52 including seven children, a group monitoring the conflict said on Saturday.

US and Arab forces have been carrying out almost daily air raids against hardline Islamist militant groups in Syria such as Daesh since last September, and US-led forces are also targeting the group in Iraq.

The British-based Observatory for Human Rights said the air raid on Friday had mistakenly struck civilians in a village on the eastern banks of the Euphrates River in Aleppo, killing members of at least six families.

The group said at least 13 people remain missing.

The United States has previously said it takes reports of civilian casualties from the US-led strikes seriously and says it has a process to investigate each allegation.

Meanwhile, state media reported that Syrian rebels shelled government-held districts in the northern city of Aleppo on Saturday, killing at least 12 civilians, including three children.

Syrian state TV said the shelling, which killed eight members of the same family, also left 45 people injured. The state news agency, quoting an unnamed police official said three children were among those killed. The official said the shells hit a residential area, damaging homes, shops and cars.

The Observatory said rebel attacks in government-controlled areas killed at least five people, including one in an overnight attack. The Observatory, which relies on a network of activists inside the country, said the death toll is likely to rise because many of the injured were in critical condition.

The discrepancy in casualty estimates couldn’t be immediately reconciled but such differences are not uncommon in the immediate aftermath of attacks.

Aleppo, once Syria’s commercial hub, became a key front in the country’s civil war after rebels launched an offensive there in July 2012. The city has since been carved up into areas controlled by the government and others controlled by an array of rebel groups.

Long a stronghold for Syrian rebels, the area, a strategic stretch because of its proximity to the Turkish border, has been a flashpoint since Daesh advanced into the region several months ago.

Syrian rebels have shelled residential areas in government-held parts of the contested city in the past, killing hundreds of people. Government warplanes have dropped explosives-filled barrels on rebel-held neighbourhoods in Aleppo and other cities, killing thousands.

On Thursday, Syrian state media said “terrorists” shelled a district in the government-controlled part of the city, killing at least seven civilians.