By Bate Felix and Adama Diarra
BAMAKO (Reuters) - Mali's junta yielded to the threat of sanctions on Sunday, pledging to start handing power back to civilians before a midnight deadline, while in the north, separatist rebels seized the ancient trading post of Timbuktu.
Amadou Sanogo, an army captain who led a March 21 coup, pledged to reinstate the constitution and all state institutions before transferring power back to civilians via elections. His promise followed last week's threat by West African regional bloc ECOWAS to impose sanctions, including the potentially crippling closure of borders around the land-locked state.
There was no immediate reaction from ECOWAS. However, the steps were two measures outlined earlier by an envoy of Burkina Faso President Blaise Compaore, the crisis mediator, as essential pre-conditions for Mali to avoid sanctions.
West African leaders are due to meet in Dakar on Monday, and will discuss Mali on the sidelines of the swearing in of Senegal's new president, Macky Sall, Senegal's APS news agency said.
Disgruntled Malian soldiers had seized power with the aim of stepping up the battle against the northern rebels. But the coup has backfired, emboldening the rebellion's Tuareg leaders to seize new ground in its quest for a northern homeland. On Sunday they took their latest target, Timbuktu, after government forces fled.
Sanogo read a statement at a barracks near the capital Bamako on Sunday ceding to ECOWAS demands. "We are making the solemn commitment to re-establish, from today, the Malian constitution of February 25, 1992 and the institutions of the republic," he said.
Sanogo, a hitherto obscure U.S.-trained captain, said the junta had agreed to consult with local political forces to set up a transition body "with the aim of organizing peaceful, free, open and democratic elections in which we will not take part".
No details were given on a timeframe or the fate of ousted President Amadou Toumani Toure, who remains in hiding.
Burkina Foreign Minister Djibril Bassolet told Reuters earlier by telephone that the steps were key to avoiding the sanctions being imposed at midnight.
"We want to be careful, we have to go gradually," Bassolet said, warning of the risk of a power vacuum. He was unreachable after the junta announcement.
Boosted by heavily armed Tuareg returning from Libya and tapping into frustrations over a lack of development in the north, MNLA rebels launched a push for independence in mid January.
The rebels have fought alongside another rebel group seeking to impose sharia law, underscoring the complex web of gunmen in a zone which is home also to local al Qaeda groups and smugglers. The MNLA denies any links with Islamist groups but there have been repeated reports of localized cooperation.
The northern administrative centre of Kidal fell on Friday, followed on Saturday by the garrison town of Gao. Timbuktu's capture essentially completes the rebels' plan to seize Mali's three northern regions, a desert territory bigger than France.
Timbuktu, for centuries a major trading post in the Sahara, was fabled for its gold, slaves and other goods, but it fell into decline even before the French 19th century occupation. Attempts to develop tourism have been hit by rising insecurity, including kidnappings of Westerners by local al Qaeda agents.
"They have arrived in the town. They are planting their flag," El Hadj Baba Haidara, member of parliament for Timbuktu, told Reuters by telephone. A resident said the MNLA rebels had planted their flag at the governor's office, the mayor's office and the main military camp.
Residents said rebels later appeared in control and there had not been any sustained resistance from Arab-led militia that remained after government forces abandoned the town overnight.
Both sources said the town was largely quiet, except for sporadic gunfire and the looting of some government buildings by armed men and civilians. Another resident, who declined to be named, said she saw government soldiers putting on civilian clothes.
In a further blow to any possible government counter-offensive, Colonel El Hadj Ag Gamou, the most trusted Tuareg in the army, told France's RFI radio he had joined the rebels with 500 men.
Western and regional nations, already critical of Toure's soft approach towards the Islamists, are likely to fret over a security void in the north exacerbated by the putsch.
While coup leaders won early support from many Malians weary of Toure's rule, the latest military defeats and the sheer scale of foreign disapproval have weakened their position.
"Everywhere it is burning," Siaka Diakite, Secretary-General of the UNTM trade union, said in a statement backed by anti-putsch politicians. "Mali cannot fight on all fronts at the same time ... Let us put our personal quarrels aside."
Ivorian President Alassane Ouattara has said he expects Toure, who has said he is safe at a secret location inside Mali, to see out the remaining two months of his mandate before a transitional national unity government is named.
"Then elections should be held between 21 and 40 days later," Ouattara, the ECOWAS head, told Ivorian television. "It is up to the political class to see if that is possible."
(Additional reporting by David Lewis in Dakar; Writing by Mark John and David Lewis; editing by Ben Harding)