Car bombs killed at least 12 people, including seven civilians, in two separate incidents in Turkish-held northern Syria on Sunday, a monitoring group said.

The first attack near a cultural centre in the town of Azaz killed seven civilians, including a young girl, the Britain-based Syrian Observatory for Human Rights said in an updated toll.

An AFP reporter at the scene saw a mangled car ablaze, sending black smoke billowing into the sky.

A man rushed away from the site of the blast, carrying what appeared to be a child wrapped in a bloodied cloth.

The Observatory said around 30 people were also wounded in the attack. 

In the second incident, a car bomb targeted a checkpoint manned by pro-Ankara rebels near the town of Al-Bab, killing five fighters, the Observatory added.

Such bombings regularly hit areas of northern Syria held by Turkish forces and their Syrian proxies.

They are usually not claimed, although Turkey routinely blames Kurdish "terrorists" linked to its outlawed Kurdistan Workers' Party (PKK).

On Saturday, explosives planted in another vehicle took the lives of eight civilians, including four children, in the city of Afrin, which Turkish forces and their proxies seized from Kurdish forces in 2018.

Syria's war has killed more than 387,000 people and displaced millions since starting in 2011 with the brutal repression of anti-government protests.

It has since evolved into a complex conflict involving jihadists and foreign powers.

Northern neighbour Turkey has seized control of several regions inside Syria in military campaigns against the Islamic State group and Kurdish fighters since 2016.