The Congolese army has been fighting rebels in the east of the country for the third day in a row, with clashes reported in villages around the town of Goma, near the country's border with Rwanda.
Soldiers backed by UN helicopter gunships battled rebels around a strategic army garrison near a mountain gorilla reserve in eastern DR Congo, as thousands of people continued to flee a three-month-old rebellion allegedly backed by neighbouring Rwanda.
The Netherlands has suspended an aid budget worth $6.15m to Rwanda over its alleged backing of the rebels.
This comes a week after the US announced it was cutting military aid to the country.
Rwanda has rejected reports made by UN experts that it is supporting the M23 movement rebels in eastern DR Congo.
UN Radio Okapi said the rebels on Thursday began attacking Rumangabo military camp, which the soldiers had only retaken from the M23 rebel group on Wednesday.
The radio station said the rebels continue to hold Rutshuru town and nearby Kiwanja, and that thousands of people had fled in recent days.
Major Olivier Hamuli, an army spokesman, said soldiers made a strategic retreat from Rutshuru "to avoid a bloodbath" of civilians.
On Tuesday, the rebels came within 25 kilometres of Goma, battling soldiers at Kibumba and forcing into flight the thousands of people who have made Kibumba a centre for refugees from a 2009 rebellion.
The rebels are accused of numerous human rights abuses including rape and forcefully recruiting children into their ranks. Soldiers also are accused of rape and widespread looting.
More than 260,000 civilians have been forced from their homes in recent months, according to UN agencies, some across the borders to Uganda and Rwanda, while others towards Goma.
Rwanda, which vigorously denies having anything to do with the rebels, this week accused Congolese troops of ill-treating Rwandan nationals.
"This is an extremely serious incident - we have confirmation that one of the tortured Rwandans has died," Rwandan Foreign Minister Louise Mushikiwabo said in a statement posted on Thursday on her ministry website.
"We have asked the government of the DRC (Congo) to ensure that the mistreatment of Rwandan citizens stops immediately."
Many Rwandans have been abused and some attacked since a UN report last month said it provided overwhelming evidence that Rwanda's military helped create, arm and support the M23 rebel group, including by sending Rwandan troops to fight alongside them against Congo's army.
The rebels are members of an earlier Rwandan-backed rebellion who were integrated into the Congolese army in 2010 and began deserting in April, demanding better implementation of a peace pact.
The United States last week announced it was cutting $200,000 in military aid to Rwanda to show it is "deeply concerned about the evidence" implicating the country.
The amount involved is small compared to all US aid to Rwanda, but it was seen as a very public rebuke from a usually staunch ally.