UN spokesman Stephane Dujarric told reporters that fighters from the National Movement for the Liberation of Azawad (MNLA) had taken the towns after clashes with Malian government forces.
“The northern towns of Kidal and Menaka are now under the control of the MNLA, and MNLA movements in Anefis, Aguelhok and other locations have been reported,” Dujarric said.
The United Nations has called for a ceasefire in northern Mali, where renewed fighting between Tuareg separatists and government forces has endangered a truce deal agreed last year.
The head of UN peacekeeping, Herve Ladsous, told journalists that the role of the UN mission on the ground was not to fight but to facilitate a way out of the crisis.
“What is needed now is a ceasefire” and to start the political process laid out in the Ouagadougou preliminary agreement of June 2013, he said.
Dujarric said humanitarian workers estimate that 3,400 residents of Kidal have fled to rural areas, Algeria and Gao since fighting erupted.
“Some 450 people have already arrived in Gao. Humanitarian agencies are sending relief items to Gao as Kidal is inaccessible to humanitarian workers from other cities.”
Mali government sources have not confirmed how many lives have been lost in clashes with the MNLA and other armed groups in Kidal since fresh fighting broke out on Saturday.
But an MNLA leader said 40 Malian soldiers had been killed and 70 taken prisoner, while 50 pick-up trucks and 12 armored vehicles had been seized along with tonnes of weapons and ammunition.
The latest military setback in a country plagued by ethnic tension but just beginning to enjoy relative stability has pushed the West African state back to the brink of chaos and state failure.
And the new round of fighting has delayed plans by former colonial ruler France to redeploy some of its troops based in Mali to begin a broader operation to hunt Islamist extremists across West Africa.