The bombing targeted a video club and a mosque in Djakana, near Cameroon’s border with Nigeria, Midjiyawa Bakari, governor of Cameroon’s far northern region, told AFP.

The victims were mostly members of a vigilante group formed to root out Boko Haram members, Bakari said, adding that they had broken a curfew designed to keep people safe at night.

Boko Haram has waged a campaign of terror on Nigeria, Cameroon, Niger and Chad. Since the Islamist group was formed seven years ago, at least 20,000 people have been killed and 2.6 million people have been displaced, according to the UN.

The new bombings are a setback for west African forces fighting Boko Haram. “Since the beginning of 2016 … the Nigerian military has had significant success in its battles with Boko Haram, particularly in terms of the amount of territory recovered,” the Armed Conflict Location and Event Data Project said on its website.