Libyan leader Muammar Gaddafi has urged an end to Tuareg revolts in Mali and Niger, saying more war will hurt the impoverished states and plunge a region unsettled by security and smuggling problems into turmoil.

Africa's fourth largest country, Libya wields influence in parts of the Sahara and the Sahel region on its southern fringe thanks to its oil wealth and tribal links between its own population and those of neighbouring states.

Speaking in the southwestern Libyan town of Ubari on Sunday evening, Colonel Gaddafi said: "I hope the insurgent leaders understand that they are playing around with a dangerous and sensitive demographic area. They are playing around with, and harming, the Islamic area.

"Do not waste time and cause hardships for children and women in the Sahara without need," he said. His comments were broadcast on state television and Libya's Jana news agency.

In both Mali and Niger, whose territories jut into the Sahara, rebels seeking more autonomy have attacked government and army garrisons and convoys over the last year in what appears to be a repeat of similar Tuareg uprisings in the 1990s.

In recent months, clashes between government troops and the desert rebels have intensified and casualties have increased.

Malian President Amadou Toumani Toure has offered to negotiate with the rebels, on condition that they release all hostages.

On Sunday, rebels released 26 soldiers who had been captured in the north-eastern region of the Kidal, the Malian government said, crediting Algerian President Abdelaziz Bouteflika with intervening to secure their freedom.

But neighbouring Niger's government has ruled out talks with its own Tuareg-led insurgents in the uranium-producing north unless they first lay down their arms.

Mali's army, backed and trained by the United States as part of Washington's "war on terrorism", accuses the rebels of trying to control cross-border smuggling routes for arms and drugs.