N'DJAMENA/NIAMEY - The armies of Chad and Niger launched a joint offensive against Boko Haram in Nigeria on Sunday, entering via neighboring southeast Niger, military sources said.
"We can confirm that Chadian and Nigerian forces launched an offensive this morning from Niger. The offensive is underway," said Colonel Azem Bermandoa, spokesman for Chad's army.
Niger military sources said troops were attacking militants from the Islamist group in Nigeria's Borno State.
On Saturday, Boko Haram officially pledged allegiance to Islamic State.