Unita had been given until midnight on May 31 to hand over towns under their control - or face economic sanctions.

The BBC's Anna Richardson reports from Luanda

Less than an hour before the deadline, a delegation arrived in the capital, Luanda from Unita headquarters in central Angola.

They said they had brought proposals from the movement's leader, Jonas Savimbi, for restoring momentum to the peace process, which has been paralysed for the last two months.

The delegation were into talks with the UN secretary-general's special representative, Alioune Blondin Beye.

The BBC correspondent in Luanda Anna Richardson says it's probable that Unita has proposed new dates for a phased handover of the remaining key towns under their control.

It remains to be seen whether their proposals will prove substantial and credible enough to stave off the threat of sanctions and win the movement yet another reprieve.

Troops of the former rebel movement

After a six-hour meeting on Saturday with the Unita leader, Jonas Savimbi, Mr Beye said the movement was refusing to make concessions on the handover of territory.

A Unita spokesman, Alcides Sakala, told the BBC that Unita accepted the handover in principle, but wanted to see the issue of human rights abuses by police dealt with first.

The UN envoy has threatened to resign and recommend economic sanctions against Unita if it fails to comply with the accords.

Mr Beye has also called on the Angolan government to improve the human rights record of the national police and to stop using state media to spread anti-Unita propaganda.

Extended deadlines

A country ravaged by war

Unita and the government fought a 20-year civil war after independence from Portugal which ended with the signing of peace accords in the Zambian capital Lusaka in 1994.

The UN has on several occasions been forced to extend its original 1996 deadline for the completion of the peace process, after Unita resisted completing the disarmament of its troops or the surrender of its territory to the government.

Last October, UN air and travel sanctions were imposed on the Unita leadership for holding up the process.