United Nations: UN Secretary-General Antonio Guterres on Tuesday urged all parties meeting in Geneva this week to discuss the Western Sahara issue to be constructive and impose no conditions for formal talks.

Morocco, the Polisario Front, Algeria and Mauritania are taking part in two days of round-table discussion with a UN envoy starting Wednesday to try to relaunch negotiations, which have been stalled since 2012.

Guterres “urges all to engage in good faith, without preconditions and in a constructive spirit in the discussions,” said a statement from his spokesman.

The UN chief expressed support for the UN envoy, former German president Horst Koehler, who is seeking to revive negotiations.

The United Nations has repeatedly failed to broker a settlement in Western Sahara, where Morocco battled the Algerian-backed Polisario insurgents from 1975 to 1991.

A UN peacekeeping mission has been deployed in the Moroccan territory since 1991 to monitor a ceasefire and organise a referendum on the status of Western Sahara, which never materialised.

Morocco insists that any negotiation on the territory should focus on its proposal for autonomy.

The United States has led a push at the UN Security Council to revive talks and has suggested that the UN mission there, MINURSO, will not remain if the parties are unwilling to seek a settlement.

The Security Council must decide on renewing the MINURSO mission before April 30.