In the eastern Democratic Republic of Congo, a tribal militia has taken control of the town of Bunia, causing thousands of civilians to flee their homes.

A United Nations official in Bunia says a Hema ethnic militia group, the Union of Congolese Patriots, controls Bunia.

According to the official, Patricia Tome, the Hema takeover has sent members of a rival ethnic group, the Lendu, fleeing the town because they fear they will be attacked.

"Many civilians, Lendu civilians, maybe are very scared of the UPC control and are fleeing the town with the militia," said Ms. Tome. "It is not confirmed yet, but what is sure that there are many neighborhoods, streets, totally empty, north of the city."

There has long been hostility between the Hema and the Lendu in eastern Congo. But it has worsened during Congo's four and a-half year war.

Uganda and other neighboring countries involved in Congo's messy war have been accused of fanning ethnic tension between the Hema and the Lendu for their own benefit.

Fighting for control of Bunia started when Ugandan troops began pulling out of the town last month. There have been several massacres during the past few days.

On Sunday, 12 people were killed, among them three babies whose throats were slit.

The United Nations has a small presence in the area, about 600 troops, and their mandate limits them to doing little more than handing out food. The troops do not get involved in clashes between Hema and Lendu.

Ms. Tome agrees that the U.N. presence needs to be stronger. But she said it is also vital for Bunia's warring parties to sit down at the negotiating table, because the reason for the violence is basically political.

"Today, the UPC is taking control again after being kicked out of the town two months ago," she said. "Tomorrow, the Lendu can come back, may come back, if they get some support and more equipment. So this is a non-ending story. Everybody has to take responsibility in order to stop this ongoing, unfortunate tragedy."

Congolese President Joseph Kabila had called for all of Bunia's armed groups to meet Tuesday in Tanzania. But it is uncertain whether the meeting will be held, since the UPC has taken control of the town.