Around 40 killed in attack on Chad military base, presidency says

President Mahamat Idriss Deby was in the area on Monday to launch an operation to track down the assailants, a presidency statement said.

The presidency blamed Sunday's attack on Boko Haram in a second statement issued later on Monday. The Lake Chad region has been repeatedly attacked by insurgencies including by Islamic State in West Africa and Boko Haram, which erupted in northeast Nigeria in 2009 and spread to the west of Chad.

There was no immediate claim of responsibility from the group.

Chad is an important ally for French and U.S. forces aiming to fight jihadists in the Sahel, which has become the epicentre of global terrorism under attack by factions loyal to al Qaeda and Islamic State.

Mali, Niger and Burkina Faso have ended military operations with the U.S. and France in recent years and turned to Russia for support instead.