The northern base is one of the major prizes amid a resumption of hostilities with Tuareg rebels in the region since August when UN peacekeepers started to pull out.

Northern Mali has seen a series of attacks on the army recently weeks which coincide with the ongoing withdrawal of the UN stabilisation force MINUSMA.

It is handing over its camps to Malian authorities and three more are due to follow this month, but the separatists claim they should be returned to their control.

The UN mission will vacate the Kidal camp and two other sites at Ansongo and Mopti in November, the foreign ministry's director for international organisations Madou Diallo said in a video posted online by the army on Monday.

After that only three camps should remain, at Gao, Timbuktu and the capital Bamako and their handover would mark the "liquidation" of UN forces in Mali.

An official with knowledge of the plan said Kidal was to be handed over November 15-30.

An army convoy of dozens of vehicles, some armoured, last week left the city of Gao, 300 kilometres (185 miles) southwest of Kidal, amid speculation about an offensive on the rebel bases in the Kidal region.

The convoy has since come under attack but on Saturday the army said its troops had taken control of Anefis, a town 110 kms south of Kidal.

Almou Ag Mohamed, a spokesperson for the Permanent Strategic Framework for Peace, Security and Development (CSP), a coalition of armed rebel factions, confirmed to AFP that the army was in Anefis.

An offensive on the rebel bases in the Kidal region could prove a turning point after a decade of conflict.

After initially launching a rebellion in 2012, the predominantly Tuareg armed groups signed a peace agreement with the state in 2015, but in August they resumed hostilities.

Attacks against Malian army camps by both the separatist groups and jihadists have increased.