The troops support a beleaguered African Union peacekeeping mission.

Ambassadors of the 26-nation alliance "started talking" about different possible options presented by military planners, said a Nato spokesperson.

Nato is currently providing air transport to the 7 000 strong AU contingent in Darfur.

Speculation is that Nato could send several hundred specialist troops into Darfur, providing logistics and command support in the transition phase between an AU and United Nations force.

Nato chief Jaap de Hoop Scheffer, who has ruled out sending combat troops into Darfur, wants alliance governments to agree quickly but no timetable for a decision has been fixed.

Three years of fighting between rebels and Khartoum-backed miltias in the Darfar region have left 300 000 people dead and two million displaced.