Ouagadougou - The lead mediator in regional efforts to end unrest in Mali told rebels there that they had to cut ties to "terrorist movements" like al Qaeda before any peace talks could begin, when he travelled to the rebel-held north for the first time on Tuesday.
Islamist militant groups control about two-thirds of Mali after hijacking a secular rebellion by Tuareg nationalists earlier this year.
They were able to rapidly seize territory in the north in the wake of a March 22 military coup in the southern capital Bamako that toppled President Amadou Toumani Toure.
West African bloc ECOWAS opened tentative contacts with rebel groups in May, and diplomatic initiatives have taken priority in recent weeks as plans for military intervention have stalled.
Burkina Faso's Foreign Minister Djibril Bassole, the bloc's mediator, met the leaders of MUJWA in the town of Gao and the leaders of Ansar Dine, which has links to al Qaeda, in Kidal.
"We can only promote dialogue at this stage, and we are doing everything we can to create the conditions for dialogue," he told journalists when he returned to Burkina Faso's capital, Ouagadougou, on Tuesday night.
"We reiterated our condition of a delimitation between Ansar Dine and terrorist movements. There hasn't yet been a formal declaration of a breaking off of operational links, but we didn't see anything that established a direct collaboration on the ground," he said.
Niger, which shares a border with Islamist-controlled areas, said on Tuesday its soldiers had killed four gunmen from northern Mali who attempted to cross into its territory to carry out a kidnapping.
Niger has led African calls for swift action to prevent extremist groups, including al Qaeda and Nigeria's Boko Haram, from consolidating their positions across the continent's loosely governed Sahara-Sahel band.
The country's foreign minister, Bazoum Mohamed, expressed doubt on Monday over the likelihood of successful negotiations with Ansar Dine and MUJWA.
"A force like that has no room for any kind of dialogue. They don't even have room for us, for our kind of praying and our normal profession of our faith," he said.
ECOWAS is pushing for the deployment of a 3,000-strong intervention force in Mali to first restore stability in the capital of Bamako before improving Mali's defeated military and helping it retake the north. But details have been sketchy.
The U.N. Security Council last month endorsed political efforts by West African leaders to end the unrest in Mali, but stopped short of backing force.
It said it was ready to examine an ECOWAS request for a U.N. mandate for intervention once more details were provided on the plans.