The United Nations mission in the Democratic Republic of Congo says it will move most of its troops to the east, where fighting is continuing.
UN peacekeepers in DR Congo are off of the troubled east
The peacekeepers will be transferred from parts of DR Congo where security has improved, said William Swing, the top UN official in the country.
This means that by mid-December more than 80% of the 10,000-strong force will be stationed in the east.
Since 1999 the area has been the scene of bitter ethnic fighting.
The killings have continued despite a national peace agreement finalised in April.
"We are implementing an entirely new redeployment plan," said Mr Swing - who heads the peacekeeping mission in DR Congo, known as Monuc.
Previously UN peacekeepers were deployed along a ceasefire line drawn up under the 1999 Lusaka accord signed by six African governments involved in the Congolese conflict.
"It no longer makes sense to keep our forces along these lines because there's no more fighting there," he said.
Mr Swing said almost half of Monuc troops will be sent to the area around Bunia, where clashes between Lendu and Hema ethnic militias have killed about 50,000 people in the past four years.
Peacekeepers will also be sent further south, to the towns of Kindu and Uvira.
Ethnic Hemas and Lendus have a long-standing land dispute, which in the past has been fanned by both Ugandan and Rwandan troops.
The UN troops will try to disarm local militias and protect civilians.
Mr Swing made the announcement in the Rwandan capital, Kigali, after meeting President Paul Kagame.
Rwanda and Uganda invaded DR Congo in 1998, saying they wanted to neutralise the threat posed by rebels across the border.
Both countries say they have now withdrawn, but have urged the UN to disarm tens of thousands of militiamen in DR Congo.