|Nomadic Tuareg tribes inhabit a large swath of the Sahara across North Africa, from Algeria to Mali
Mali's army has said it fought off attacks by Tuareg rebels, some of whom recently returned from fighting in Libya and have launched an offensive to seize several northern towns.
Fighting was ongoing in the towns of Menaka and Tessalit on Thursday, according to both rebel and government forces.
Rebel and government forces both claim to be in full control of the town of Aguelhoc.
Fighting erupted in Aguelhoc and Tessalit on Wednesday morning, keeping residents indoors as gunfire was exchanged, a day after the army said it had fought off an attack in the town of Menaka by bombing rebel positions.
"Contrary to what the attackers say, we have forced them to withdraw in Tessalit and Aguelhoc," a military source from the regional army headquarters in Gao told the AFP news agency.
Lieutenant Oumar Toure, an army officer, said the military "would not allow anyone to meddle with Mali's sovereignty".
"The instructions are clear: Don't hurt civilians, but use all your energy to hunt down the criminals," he said.
Sources told Al Jazeera on Thursday that the army was conducting house raids and arrests in the northern towns of Gao and Kidal, targetting Tuareg tribal sheikhs, as well as Tuareg military and political figures.
Local government officials in Tessalit and Aguelhoc reported heavy weapons fire on Wednesday as the rebels attacked military camps in the two locations.
"Our aim is to flush out the Malian army in several northern towns," said a Tuareg rebel spokesman, who called himself "Moussa Salam", in a telephone interview.
Military camps 'seized'
On Tuesday, fighting lasted several hours as rebels tried to seize control of Menaka, south of Aguelhok, which is not far from the Niger border. The government reported the deaths of several Tuareg and one soldier during Tuesday's fighting.
Army helicopters bombed rebel positions, forcing them to withdraw to a forested area near the town. However, the Tuareg maintained they held control of the town's two military camps.
On Wednesday, shops were closed in the town and sporadic shooting was heard near a camp on the outskirts of the town, a local journalist told the AFP news agency.
"For the moment it seems as if the rebels are in control," he said.
The Gao military source said re-inforcements had arrived in Menaka on Wednesday and would "occupy one of the camps".
In a statement it said the assailants "included forces that returned from Libya and comprised elements known as the Azawad National Liberation Movement (MNLA)".
Hundreds of armed Malian Tuareg recently returned from Libya where they fought alongside troops of toppled leader Muammar Gaddafi.
The MNLA is a movement with no known leader which was founded at the end of 2011 after a fusion of rebel groups, including the Northern Mali Tuareg Movement (MTNM) whose leader died in a road accident last year.
"This new organisation aims to free the people of Azawad from the illegal occupation of its territory by Mali," the organisation said in its first press statement in October 2011.
The Azawad, a region considered the birthplace of the Tuareg, stretches from the west to the north of Mali. A nomadic community of some 1.5 million people, Tuareg are scattered between Algeria, Burkina Faso, Libya, Niger and Mali.
Mali and Niger experienced uprisings as the Tuareg fought for recognition of their identity and an independent state in the 1960s, 1990s and early 2000 with a resurgence between 2006 and 2009.
Following these rebellions many fighters left for Libya, where they were integrated into Gaddafi's security forces. After his fall they returned to northern Mali, particularly the Azawad region between Timbuktu and Kidal.
The return of the rebels has added to Mali's woes as the region battles al-Qaeda in the Islamic Maghreb (AQIM), which has carried out many attacks on troops, kidnappings of Westerners and various trafficking operations, including drugs.