Two separate car bomb blasts in Turkish-controlled north Syria on Tuesday killed eight people, including two civilians, a Britain-based war monitor said.
On the outskirts of the town of Al-Bab, explosives planted in the car of a police chief from another district detonated and killed him, two policemen accompanying him, and two civilians, the Syrian Observatory for Human Rights said, adding 19 people were wounded.
And in the town of Afrin, a car bomb went off near a bakery, killing three people and wounding 16 others.
Turkey and its Syrian proxies control several pockets of territory on Syria's side of the border following three military incursions since 2016, against Islamic State group (IS) and Kurdish fighters.
There was no immediate claim of responsibility for either bombing.
But there have been a string of attacks in Al-Bab since its capture by Turkish troops from IS in 2017.
Several have also hit Afrin, which Turkey and its Syrian proxies seized from Kurdish fighters in 2018.
UN humanitarian official Mark Cutts deplored "another horrific car-bomb in Al-Bab today with more civilian casualties".
"Car-bombs remain a deadly scourge in Syria," he tweeted.
US-backed Kurdish forces seized the last scrap of that territorial proto-state from the jihadists in eastern Syria in March last year.
But the jihadist group continues to carry out attacks through a network of sleeper cells operating in some regions it used to control.
Syria's civil war has killed more than 380,000 people since it started with the repression of anti-government protests in 2011.