Malians living under al-Qaida-linked rebels have expressed dismay that it could be nearly a year before a regional military intervenes to oust the Islamists from power.
The UN's most powerful body on Thursday authorised an African-led force but made no mention of size and set no timeline for action.
The UN peacekeeping chief, Herve Ladsous, said recently he did not expect a military operation to begin until September or October of next year.
"We want rapid military action to liberate our cities," said Alphadi Cisse, who lives in Timbuktu. "There is no school, there is no work and no money. We are fed up with this situation."
The mayor of Timbuktu, which is controlled by the Islamist group Ansar Dine, has described conditions there as "a living hell". The militants have imposed their version of strict Islamic law known as sharia. They have stoned to death a couple accused of adultery, hacked off the hands of thieves and have recruited children as young as 12 into their ranks. Heavily armed men have also attacked bars that sell alcohol and banned men and women from socialising in the streets.
The turmoil has decimated the economy of Timbuktu, once a thriving tourist town.
Thursday's resolution, adopted unanimously by the UN security council, welcomes troop contributions pledged by Ecowas and calls on member states, including from the neighbouring Sahel region, to contribute troops to the mission. Council diplomats say the best-trained African troops in desert warfare are from Chad, Mauritania and Niger.
The resolution stressed that there must be a two-track plan – political and military – to reunify the country, which has been in turmoil since a coup in March. Islamist groups were able to take hold of northern Mali, an area the size of Texas, after the coup created a power vacuum.
Coup members created fresh turmoil earlier this month when they arrested the country's prime minister and forced him to resign – a move that raised new concerns about the ability of the Malian military to help regain control of the north.
The UN resolution also emphasises that further military planning is needed before a force can be sent and asks the secretary general, Ban Ki-moon, to "confirm in advance the council's satisfaction with the planned military offensive operation".
France's UN ambassador, Gerard Araud, told reporters that it was premature to say when the military operation would take place because African and Malian troops had to be trained and much depended on the political process and the country's extreme weather.
Northerners in Mali say the longer the world waits, the more entrenched the militants are becoming.
Hamadada Toure, a teacher from the city of Gao, urged the international community to follow through swiftly on its pledges to help free the north.
"If the resolution is not acted upon to chase the Islamists out of towns, all the comings and goings of diplomats and the mobilisation of the international community are a bluff," he said from southern Mali, where he sought refuge earlier this year.
