Chadian troops killed 19 insurgents after Boko Haram attacked an army post on the fringe of Lake Chad, a Chadian security source said, adding a Chadian soldier was also killed in the shootout.

Boko Haram attacked the post of Konguia at around five in the morning, the source said, speaking on condition of anonymity. The army responded, killing 19 Boko Haram members. A soldier died and the attackers fled to Nigeria.

Chad, Niger and Cameroon have joined a multinational force to counter the growing threat that Boko Haram poses in the region.

The group’s home ground is northeastern Nigeria, where it has killed thousands of people in a six-year campaign to establish Shariah, or the so-called Islamic law.