Video footage shows car bomb rips through manned checkpoint in Syria
A videograb shows the bombing in Al-Bab, Syria.
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).
In another attack, a car parked near a cultural centre in the town of Azaz killed seven civilians, including a young girl.
A witness 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.
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 extremists and foreign powers.
Northern neighbour Turkey has seized control of several regions inside Syria in military campaigns against the Daesh group and Kurdish fighters since 2016.
Agencies
