A Chadian military source says 11 Chadian soldiers were killed Tuesday in a cross-border attack by suspected Boko Haram militants.
The source told reporters that 17 Boko Haram fighters were also killed in the clash. The militants reportedly attacked a Chadian army position near Lake Chad around 4 a.m. local time.
Chad is a leading contributor to a regional joint task force set up to fight Boko Haram. The group's attacks have spread in recent years from its birthplace in northeastern Nigeria to nearby Chad, Cameroon and Niger.
Chadian forces helped Nigeria reclaim areas controlled by the group in an offensive early this year.
Boko Haram has killed more than 10,000 Nigerians since 2009 in an effort to set up a strict Islamic state. Fighting in the northeast has displaced more than 2 million Nigerians from their homes.