The heads of state from Burkina Faso, Chad, current African Union chair Congo and Sudan as well as Libyan leader Moamer Kadhafi are due to hold talks in Tripoli on Wednesday.

Libyan Foreign Minister Abdel Rahman Shalgam, meeting with African counterparts to prepare for the summit, underscored the "vital importance of the meeting and the need for all sides to contain the tensions between Chad and Sudan."

Tension between Khartoum and Ndjamena has mounted since Chad in December declared a "state of belligerence" with Sudan after a series of border clashes, when each country accused the other of support for rebel groups.

New York-based Human Rights Watch on Sunday called for the deployment of an international force to protect Chadian villagers from what it described as almost daily cross-border raids by militias based in Sudan's troubled Darfur region.

It accused Sudanese and Chadian militiamen from Darfur of killing local people, burning villages and stealing cattle, some apparently with Sudanese government support, including with helicopter gunships.

Darfur has since February 2003 been wracked by conflict between two rebel groups fighting Khartoum's troops and their allies, an Arab militia called the Janjaweed.

The conflict has killed some 300,000 people and displaced two million others in nearly three years.

Sapa-AFP