The United Nations has officially taken over peacekeeping operations in the troubled Democratic Republic province of Ituri from a French-led force.
UN troops are allowed to use force if necessary
The French deployment in the Ituri capital of Bunia has ended the bitter ethnic clashes in the town.
However, fighting has continued elsewhere in the north-eastern province, where some 50,000 people have been killed since 1999.
An ethnic Hema militiaman said some 200 people had been killed in Fataki, 60 km north-west of Bunia in recent clashes.
The head of the UN peacekeeping force said they would move to end the violence across the whole province.
"Our role is not only to consolidate what has been achieved but also to extend security over the rest of Ituri," William Swing, the head of the UN Observer Mission for Congo (Monuc), said at the handover ceremony.
Monuc has some 2,500 troops in Ituri, from Bangladesh, India, Nepal, Pakistan and Uruguay, reports the UN news agency, Irin.
French troops are leaving Bunia in good spirits, says the BBC's Andrew Harding, convinced that their mission has been a success.
And he confirms that they have stabilised the situation in Bunia.
But a Monuc spokesman confirmed that there had been recent fighting in Fataki, which was now empty of residents.
"The state of the burnt houses indicated that the latest attack took place on Friday [29 August] or Thursday [28 August]," said Leo Salmeron after two Monuc helicopters had flown over the town.
An official with the Union of Congolese Patriots militia, Saba Rafiki, said their ethnic Lendu rivals had been attacking and looting since mid-July.
The French-led peacekeepers arrived in June to try to stop tit-for-tat massacres in Bunia.
Hundreds of lives had been lost in a matter of weeks in fighting between ethnic Hemas and Lendus.
The European Union force's mandate was limited to Bunia, the capital of Ituri district, and its immediate surroundings.
But the UN force is being asked to maintain peace throughout the entire Ituri province.
Some UN combat helicopters have started flying over the outskirts of the town, to try to intimidate hundreds of militiamen who are still active in the bush outside Bunia.
The UN soldiers will be working under a Chapter Seven mandate which allows them to use force if necessary.
Ethnic violence between the majority Lendu and the minority
Hema ethnic groups in the region has displaced some half a million people.
A new power-sharing government involving former rebels is now up and running after five years of clashes, which left some three million dead and became known as Africa's bloodiest war.