The Malian army, supported by French forces, has retaken control of two key towns from rebels after fierce fighting on the ground in central regions of the country.
French and Malian troops wrested control of the strategic town of Konna, located about 700 kilometres from Bamako, and Diabaly which is 400 kilometres north of the capital of the sprawling country on Friday.
A spokesperson from the al-Qaeda-linked Ansar al-Dine rebel group confirmed to Al Jazeera’s Mohammed Adow that its fighters pulled out of the town of Konna.
"They withdrew from the town after [incurring] huge casualties in the fighting in the town. They say they will continue their fighting in other parts of the north of Mali," Adow said from the Malian capital Bamako.
He said that fighting is continuing in other towns where French and Malian forces have admitted encountering "stiff resistance" from rebel fighters.
In Diabaly, which the rbels had seized on Monday even as their bases were pounded by French fighter jets, local sources reported the rebels had been driven out.
"Diabaly is freed, the Islamists have left and the French and Malian troops have entered the town," said a member of the local municipal council. Her statement was confirmed by a regional security source.
Armed groups that have controlled northern Mali since April pushed south into government-held territory and seized Konna, about 700km by road from Bamako, on January 10.
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The takeover prompted former colonial ruler France to intervene to stop the rebel advance. Initially the French role was limited to air power, but it has since launched ground offensives with troops.
The area is not accessible to independent observers.
Nigeria has boosted its troop allotment for Mali to 1,200 soldiers from 900 planned earlier as part of an African force
aimed at helping to retake the north, officials said Friday.
In a letter to the country's Senate on Thursday, President Goodluck Jonathan said he had, "in consultation with the National Defence Council, approved the development of a contingent of 1,200 members of the armed forces."
It said the soldiers would be deployed "for limited combat duties". Nigeria will also command the African force.
In urging the Senate to approve the deployment, Jonathan said he had concluded that "our national security is under imminent threat or danger as a result of the crisis in northern Mali".
The Senate approved the deployment on Thursday, Senator Ita Enang, chairman of the body's business and rules committee, confirmed on Friday.
A contingent of 80 Nigerian troops departed for Mali on Thursday as part of the UN-mandated African force, and military officials spoke then of a total of only 900 troops. It was not clear when the remainder of the troops would arrive.
Meanwhile, the UN refugee agency said it anticipated as many as 700,000 more people in northern Mali will be forced to flee their homes in the next few months because of the fighting.
Melissa Fleming, UNHCR’s spokeswoman, said the agency is planning for the additional displacement of up to 300,000 inside Mali and 407,000 flowing into neighbouring countries.
Fleming said the agency is urgently reinforcing its teams across the region as thousands more refugees flee to Mauritania, Burkina Faso, Niger, Algeria, Guinea and Togo.
The agency says that during 2012 close to 200,000 people fled their homes in northern Mali and are on the move within the country, while 144,500 Malians crossed into neighbouring countries.