"We will have to fight," he said.
Mali's neighbours in the regional bloc, Ecowas, will seek a mandate this week from the UN for an invasion force to reconquer the north within weeks, said Ivory Coast President Alassane Ouattarra.
Diplomats expect the force will include troops from Niger, Nigeria, and possibly Chad, as well as Mali itself, paid for by Western donors.
Cisse said the economy in the fabled centre of Islamic scholarship has been destroyed along with many of the city's centuries-old monuments.
The population was on the point of starvation and held out almost no hope that the bickering and ineffective junta - and its civilian partners in the south - would rescue it.
"I do not believe in the power of the Malian army to solve this crisis because they deserted the cities, leaving behind weapons that the rebels are now using against us."
The plight of Timbuktu captured the world's attention when hardliners from the Ansar Dine guerrilla group began to demolish shrines and mausoleums which they claim violate their strict interpretation of Islam. Concern has grown over the priceless ancient manuscripts collected in Timbuktu dating back to when the city was a major centre of learning.
Cisse said that people refused to follow the Sharia law imposed by the armed groups and would never support the "destruction of our sites". He said the former tourist destination had become a ghost town. Residents have organised demonstrations but have been warned that they risk being executed by the gunmen in charge.
"We try not to give them opportunities to shoot at us," said the mayor.
Mali, on the southern edge of the Sahara, has been overwhelmed by a sequence of crises that began with the fall of Muammar Gaddafi's regime in Libya. Regime change in Tripoli saw hundreds of pro-Gaddafi fighters from the Tuareg ethnic minority pour back into northern Mali - many of them heavily armed and well trained.
Calling themselves the MNLA, they declared a new uprising against the Government in Bamako which has long been accused of marginalising the majority Tuareg areas in the north.
Government forces were quickly routed, prompting a mutiny by troops in the capital and the emergence of a military junta. The international community has condemned the coup and refused to recognise the north's independence.
- Independent