There has been a further flare-up of fighting in the Democratic Republic of Congo with mortar and small-arms fire around the north-eastern town of Bunia.
The UN has been unable to halt clashes in the area
Ethnic Hema militias of the Union of Congolese Patriots (UPC) who took the town earlier this month said they repelled an attack by their Lendu rivals.
Meanwhile a spokeswoman for the United Nations World Food Programme told the BBC that 50,000 refugees from Bunia had reached the town of Eringueti, 100 kilometres (60 miles) south of Bunia.
Aid agencies are now trying to reach them to assess their needs.
More than 300 people were killed in Bunia in ethnic fighting earlier this month.
International help sought
The United Nations is considering sending a peacekeeping force to the region.
UN undersecretary general for peacekeeping Jean-Marie Guehenno visited Uganda on Tuesday for his latest stop in an attempt to drum up support for an international force.
France has been asked to lead this force and provide a battalion with up to 1,000 troops, but has insisted that other nations join in and that a deployment be for a limited period.
Militia leaders have said they will treat any French troops who go to Bunia as enemies.
The UPC says the French back Congolese President Joseph Kabila, whom the UPC says is helping the Lendus.
Two groups - Hemas, traditionally cattle-raisers, and Lendus, predominantly farmers - have been in conflict for centuries for land and other resources in the area.
The rivalry has become more bloody because the Ituri district around Bunia is rich with gold.
Neighbouring nations involved in the civil war - Uganda and Rwanda - armed both sides as proxy militias.
The clashes in the area around Bunia erupted soon after the 9,000-strong Ugandan forces withdrew from Bunia about two weeks ago as part of the peace deal in DR Congo.
The Lendus are the majority in Ituri but some accuse former colonial power Belgium of favouring the Hemas.