Fresh fighting has broken out in the town of Bunia in the Democratic Republic of Congo. A U.N. official in the town says fighting between rival ethnic groups has led to at least five deaths. Dino Mahtani, recently back from Bunia, reports from the Congolese capital Kinshasa.

Rival ethnic Hema and Lendu militias clashed on the outskirts of Bunia on Tuesday. According to Colonel Daniel Vollot, the U.N. commander in charge in the town, a nearby village was also burned down.

The fighting effectively ends a cease-fire that was brokered between the rival militias and Congolese President Joseph Kabila in the Tanzanian capital two weeks ago. Bunia is located in the northeastern part of the DRC, in the mineral rich province of Ituri.

Both Hema and Lendu militias have been used as proxy fighting forces by the Rwandans and Ugandans, who since their invasion in 1998 have been fighting each other for control of the area, which is abundant in gold, diamonds and coltan, a mineral essential in the production of mobile phones.

In early April, nearly 1000 Hema civilians were massacred in the Bunia area by Lendus supported by Ugandan troops.

But since the withdrawal of Ugandan troops earlier this month, the Hema militia have managed to regroup and assert their presence in Bunia, using weapons left behind by the Ugandans and support from Rwanda.

The latest fighting will come as a blow to the international community. The U.N. undersecretary general for peacekeeping operations, Jean Marie Guehenno, was recently in Bunia to try and convince locals that a multinational rapid reaction force was on its way to deal with the conflict that has claimed more than 50,000 lives and displaced over half a million in the last four years.

Tuesday's attack has left the Hema in even greater control of the town. They have pushed past the old office of the local Lendu leader and are driving the Lendus even further back into the forests surrounding Bunia.