At least one civilian was killed and more than 16 wounded on Tuesday by two bombs hidden in motorbikes in the Syrian border town of Azaz, which is controlled by Turkey-backed rebels, two witnesses and a security source said.
They said the first booby-trapped motorbike exploded at a busy thoroughfare in the bustling town near the Turkish border killing one person and wounding at least 11 others.
At least five more people were wounded when another motorbike exploded an hour later near a mosque close to the first blast, a witness said.
A third motorcycle in the town of Rai to the east of Azaz that is also under control of Turkey-backed rebels was found before it exploded, a police security source said.
Rebels have long accused the powerful Kurdish YPG militia of carrying out blasts they say seek to sow fear in areas where Turkey has carved a sphere of influence with the help of Syrian Arab rebels it backs and arms.
There was no immediate comment from the YPG, which clashes sporadically with Turkey-backed rebels from areas it controls to the south of Azaz and has denied previous accusations of attacks on civilians.
The YPG says it targets Turkish forces that it says occupy the mainly Kurdish populated city of Afrin to the west, which rebels and Turkish troops seized last year.
Turkey regards the YPG as a terrorist group tied to the PKK inside its own borders, and has staged incursions into Syria in support of Syrian rebels to push it from the Turkish border.