Some 20,000 people have crossed the border into Uganda to escape fighting in the eastern Democratic Republic of Congo, Ugandan officials have said.
The Congolese army is working with UN troops in eastern DR Congo
A Ugandan military spokesman said the refugees were being offered help.
The fighting is centred on the DR Congo town of Rutshuru, 90km (56 miles) from Bukavu, the scene of previous clashes.
UN officials said the Congolese army had sent reinforcements to the area, which it says came under attack from rebels loyal to a former army chief.
The governor of North Kivu province, Eugene Serufuri, said the dissidents fled when the reinforcements arrived.
The rebels, who follow renegade former general Laurent Nkunda, had reportedly briefly occupied a number of towns and villages around Rutshuru since Thursday.
Gen Nkunda's forces seized nearby Bukavu, the capital of South Kivu province, from the government for a short period in summer 2004.
The United Nations refugee agency, UNHCR says more than 20,000 people had fled into Uganda to avoid the latest fighting.
A Ugandan military spokesman said the refugees were being taken from Uganda's border post at Bunagana to the district town of Kisoro for resettlement.
The Congolese army, backed by UN peacekeeping forces, has recently been engaging rebel groups in eastern DR Congo in an effort to drive them out ahead of elections planned for later this year.
About 40 people have died in recent months, in fighting between Ugandan-based rebels and Congolese and UN forces.
The east has been out of the control of central government for many years.
Despite an official end to the civil war in 2003, bands of militia groups still terrorise civilians and use the rich minerals and timber of the region to finance their operations.
Several neighbouring countries were drawn into DR Congo's brutal five-year conflict which led to some 3m deaths.