A French member of the European Union security force in Chad is missing after a vehicle strayed into Sudan and drew fire from troops there.
An unarmoured vehicle accidentally went three kilometres beyond the Sudanese frontier in the Tissi region, the force said.
An attempt to recover the vehicle ran into enemy fire, and the rescue group was forced to leave the area, leaving one member of the European force missing, the force added.
The 3,700-strong EUFOR has a UN mandate to provide security for more than 400,000 people in eastern Chad. More than half of the force will be provided by France.
EUFOR is commanded from Europe by Irish Maj Gen Pat Nash and in Chad by French Brig Gen Jean-Philippe Ganascia.
Fifty members of the Irish Army's Ranger wing arrived in the central African country last month as part of the mission's entry force.