The United Nations security council has extended the mandate of its peace- keeping force in Western Sahara for another six weeks as it tries to get agreement on a date for the planned referendum on the territory's future.

The council called for an end to delays and urged Morocco, which occupied most of Western Sahara in the mid-seventies, and the Algerian-backed Polisario Front to agree by mid-November on who will be eligible to take part.

The referendum will ask voters to choose between independence and integration with Morocco.

Earlier this week, the UN secretary-general, Kofi Annan, suggested that the vote -- which has already been delayed nearly seven years -- be put back again from December this year to December 1999.