Tuareg rebels in northern Mali have seized a strategic border town, as the United Nations urges an end to the fighting.

Rebel fighters said Wednesday they seized the town of Tinzawaten, and government forces confirmed they made a “strategic” retreat. The government troops withdrew across the border into Algeria.

United Nations Secretary-General Ban Ki-moon said Wednesday he is “deeply concerned” about the civilian casualties and large numbers of people displaced from the fighting. In a statement, Mr. Ban called on the rebels to immediately end all attacks and to use talks with the government to resolve their grievances.

Tuareg rebels launched a new rebellion on January 17, clashing with government troops in several northern towns. The United Nations refugee agency says at least 22,000 people have fled the unrest in northern Mali.

Hundreds of ethnic Tuaregs recently returned to northern Mali from Libya, where they fought alongside troops loyal to ousted leader Moammar Gadhafi. The government has been holding talks in recent months in an effort to defuse rising tensions in the north.

Meanwhile, a fact-finding mission from the West African regional bloc ECOWAS is scheduled to arrive in Bali's capital, Bamako, on Thursday to determine the extent of the security and humanitarian situation.

ECOWAS Communications Director Sonny Ugoh told VOA that his group hopes Mali's government will engage with the Tuareg rebels in order to resolve the crisis.

“It will be in the best interest of the sub-region, and Mali, for the insurgents to dialogue with the government of Mali. That way their concerns behind the rebellion will be addressed.”

Tuareg rebels say they are seeking independence from the southern-based government, which they say has ignored Mali's impoverished northern desert region.

Tuareg nomads are present throughout the Sahel region of Africa. Both Mali and Niger have battled Tuareg uprisings in the last decade.