Chad says it has killed 1,000 jihadists in an operation in the Lake Chad area against the Islamist militant group Boko Haram.

Army spokesman Col Azem Agouna said 52 Chadian soldiers were killed during the six-day battle, known as Bohoma’s Anger.

President Idriss Deby has visited Lake Chad. He said not a single Boko Haram fighter remains on the islands where the jihadists had their hideouts.

He said it was regrettable that Chad had been left on its own to fight on the lake, a vast marshy area where the borders of Nigeria, Niger, Cameroon and Chad converge.

The offensive was launched after suspected Islamists last month killed nearly 100 Chadian troops during a seven-hour attack on an island base.

There has been no independent confirmation and Boko Haram has not commented on the claims.