The latest round of U.N.-led peace talks between Morocco and the pro-independence Polisario Front ended in stalemate Wednesday, with the two sides agreeing to try again in March to resolve a 32-year dispute for control of Western Sahara.

U.N. mediator Peter van Walsum said the two sides could not reach a “mutually acceptable solution to the impasse.” They were the third such round of talks since last year.

The U.N. Security Council had said there should be no “preconditions” to the negotiations.

None of that appeared to help much.

“During the two days of discussions, the parties continued to express strong differences on the fundamental questions at stake,” Van Walsum said.

He said the two sides did finally agree “on the need to move the process into a more intensive and substantive phase of negotiations.”

The conflict has gained in importance to Western nations as they try to pressure North African countries to contain the growing violence in the region linked to al-Qaida and radical Islamists.

Morocco assumed control of Western Sahara in 1975, after Spain withdrew as a colonial power. The Polisario Front also wants control of a desert area rich in phosphate and other resources.

The United Nations brokered a ceasefire in 1991, and now spends $46 million a year on more than 500 peacekeeping personnel, mostly military observers and local civilians.

But the Polisario guerrillas, backed by neighboring Algeria, threatened to resume fighting because Morocco did not hold a promised referendum on self-determination for the Saharawis in the region.

Algeria and Mauritania also were consulted during the talks, Van Walsum said.

The Polisario Front had wanted Morocco to agree to “confidence-building measures” such as eliminating land mines in Western Sahara and improving the human rights situation, but there was no agreement reached on those issues.