NMLA spokesman Mossa Ag Attaher, though, denied that the rebels were stepping up their armed presence. He said they were there "rather to strengthen contacts between NMLA members outside Kidal and those inside the town."
The Tuareg rebels have sought independence from Mali for decades and launched their latest rebellion in early 2012. After being sidelined by the jihadists, they regained control of Kidal earlier this year, even as other northern cities were retaken by the Malian military.
Malian soldiers ultimately returned in time for the July presidential election and subsequent runoff, though participation in Kidal was meager.
The dispute over the administrative buildings has prompted protest in Kidal, and fears of insecurity have been further compounded by suspicion that Islamic extremists have returned. The killing earlier this month of two French radio journalists in the area highlighted the perilous security situation.
Elsewhere in the north, mortar shells fell near a military camp in Menaka in the country's northeast. Suspicion immediately fell on MUJAO, a radical al-Qaida-linked jihadist group that has claimed responsibility for a series of attacks in the Gao region since its ouster from power.
A Malian security official stationed in the region, who spoke on condition of anonymity because he was not authorized to speak to journalists, said there had been no victims in the attack early Friday.