A delegation of U.N. and African officials has told the military junta that seized power in Mali on Wednesday night to hand back power, saying its plan to fix Mali's problems and restore security before stepping down will not work.

The message was delivered on Friday during a lightning visit by U.N. and African Union officials and the head of the regional ECOWAS Commission, the U.N. Secretary General's special representative for West Africa, Said Djinnit, told Reuters by phone on Saturday.

Mutinous low-ranking soldiers seized the presidential palace and Mali's state television this week, dissatisfied with President Amadou Toumani Toure's handling of a rebellion by northern nomads launched in January.

Rumours swirled around Bamako on Friday that junta leader Captain Amadou Sanogo had been killed in a counter-coup by Toure loyalists. Early on Saturday, state television showed Sanogo insisting he was well, but it was not clear when the footage had been recorded.

The coup leaders have said they plan to restore security and equip the army to better fight a northern Tuareg rebellion.

We warned them that this would not work and that the restoration of constitutional order was unconditional, Djinnit said, adding that the coup leaders did not have a timeframe to hand back power.

The time is not with them. The more they stay, the more it gets complicated. That's the message, Djinnit added.

Sanogo heads the National Committee for the Return of Democracy and the Restoration of the State (CNRDR), a body set up by soldiers after the coup on Wednesday.

ISOLATED

Toure has not been heard from since the coup, although the African Union said on Friday it had been told that he was still in Mali, not far for Bamako, being protected by loyal forces.

The international community has urged a rapid return to constitutional rule and a coalition of Malian parties said elections, which had been scheduled for April, should be held as soon as possible.

ECOWAS, the Economic Community of West African States, said it would not recognise the junta and has scheduled a summit in Abidjan on Tuesday to discuss the Mali crisis.

Djinnit said the bloc would probably follow the African Union's move and suspend Mali.

They (the junta) made an appeal to us to help them. We said we can only help you after the restoration of constitutional order, he said.

Bamako was quiet on Saturday, with people back out on the streets, but most shops shut.

Traffic was thin, mainly due to fuel shortages as most petrol stations remained closed following two days of looting and hijacking by mutinous soldiers.

Reuters reporters saw a convoy of three large petrol trucks being escorted into Bamako by security officials on Saturday.

There were fewer soldiers on the streets but the roads around state TV remained cordoned off with makeshift roadblocks manned by jumpy soldiers.

We were afraid, but the soldiers have encouraged us to come out and sell our goods without fear, said Alimata Traore, a trader in one of Bamako's markets.

FRONTLINE

The northern rebel MNLA, whose numbers have been swollen by Malian Tuaregs returning from the ranks of Libya's army after the fall of Muammar Gaddafi, launched their fight for an independent north in January.

Aiming to capitalise on confusion in the capital, they have pushed south to occupy positions abandoned by government forces.

The governor of the northeastern region of Kidal told Reuters late on Friday that government troops had retreated from the frontline after they heard of the coup in Bamako.

We are now surrounded (in Kidal city) by rebels of the MNLA. The current situation in Bamako contributed much to the weak commitment of soldiers on the frontline, Colonel Salifou Kone told Reuters by telephone.

Sanogo has said he is ready to negotiate with the rebels but that his aim is to maintain Mali's territorial integrity.

Hama Ag Mahmoud of the MNLA's political wing told Reuters in Nouakchott, the capital of neighbouring Mauritania: We are ready to negotiate but there are conditions - the incumbent must be well-established, representative and have the political class behind him, and we must have guarantees from big powers.

(Additional reporting by Adama Diarra in Bamako and Laurent Prieur in Nouakchott; Writing by Bate Felix; Editing by Robin Pomeroy and Kevin Liffey)