Boko Haram killed at least 70 people Wednesday in Cameroon near the border with Nigeria.
The Islamist militants attacked Muslims gathered for morning prayer at a mosque in Fotokol and other civilians in their homes, local officials said.
Cameroonian and Chadian forces confronted the militants as they were attacking people in their homes. An unconfirmed number of militants were killed.
On Tuesday, Chadian forces had forced Boko Haram out of Fotokol into the Nigerian town of Gamboru, where 200 militants were killed. Nine Chadian soldiers died.
The African Union recently agreed to deploy troops to battle Boko Haram.
Boko Haram was designated as a foreign terrorist organization by the U.S. State Department in 2013. The militant Islamic group seeks to establish an Islamic state in Nigeria and has ruthlessly targeted civilians.