A rescue worker said one civilian was killed after an improvised explosive device went off in a vehicle near a transport office in the city of Azaz, which lies near the main border crossing with Turkey.
A few hours later a suicide bombing in a market place in the town of al Bab wounded three and killed the suspected bomber, a police source said.
This was followed minutes later by another suicide bombing at a roundabout in the city of Afrin, a mainly Kurdish area which Turkish forces and their Syrian allies took from the People’s Protection Units (YPG) in 2018.
Main towns in the northwestern border area, run by Syrian Arab rebels backed by Turkey, have in the last year been frequently hit by bombings detonated in crowded civilian areas.
Turkey and its allied rebels say the blasts aim to make ungovernable an area populated by more than 3 million Syrians who have fled government-controlled areas during the country’s decade-long civil war.
Turkish-backed Arab rebels in Azaz and other parts of the enclave have blamed previous blasts on the YPG, which controls some areas in the northwest and holds sway over swathes of Syria’s northeast.
The YPG has in turn accused Turkey of killing civilians in drone strikes during a war of attrition waged by Ankara over YPG-held territory in north Syria.
Turkey considers the YPG an extension of the Kurdistan Workers Party (PKK).
Ankara made incursions into Syria in support of Syrian rebels.
Ankara retains a large military presence in the area, deploying thousands of troops in what is the last rebel enclave.
Reporter's code: 50101