Thousands of refugees at a camp in eastern Democratic Republic of Congo must be moved before they are caught up in fighting, aid officials have warned.
More than 60,000 displaced people are at the Kibati camp, close to the front line separating government troops and rebels loyal to General Laurent Nkunda.
They are among 250,000 who have fled the violence which flared in August.
Fighting has stopped aid from reaching Kibati and forced many there to flee south to the provincial capital, Goma.
"We noticed these people might be in serious danger and the humanitarian community decided we should move them from there... as soon as possible," Ibrahima Coly, the head of the UN refugee agency in the North Kivu region, told the Reuters news agency.
Aid agencies would transport those who agreed to a safer camp west of Goma, hopefully starting in a week's time, he said.
On Wednesday, the head of the UN mission in DR Congo, Monuc, appealed for 3,000 extra troops, saying he did not have enough to protect civilians.
Gen Nkunda's rebels - who are demanding protection from Rwandan Hutu rebels who fled to DR Congo after Rwanda's 1994 genocide - have told the AFP news agency they have advanced to the outskirts of Kanyabayonga, a strategic town 100 km (60 miles) north of Goma.
Government forces were accused of looting and raping civilians there earlier in the week. The UN has accused both sides of war crimes during the latest upsurge in violence.
Meanwhile, there is increasing evidence that foreign forces are being drawn into the conflict.
Eyewitnesses have told the BBC that Angolan and Zimbabwean troops are on the ground, and journalists are reporting that some of the rebel fighters are in the pay of the Rwandan army.
This has renewed fears that the fighting will see a re-run of the five-year Congolese war, the largest on the continent in recent times.
During the war, which erupted in August 1998, Congolese government forces supported by troops from Angola, Zimbabwe and Namibia were fighting rebels backed by Uganda, Rwanda and Burundi. Forces from Chad and the Central African Republic were also involved.
A Goma resident told the BBC that Angolan soldiers had been supporting Congolese government forces.
"We are seeing soldiers wearing Congolese army uniform here in town but they are not speaking the same language like us," he said.
"They are patrolling but unable to communicate with the population. These are speaking Portuguese," he added.
Experts say this evidence is not conclusive, since some Congolese troops fought in Angola during their civil war and frequently converse in Portuguese. Angola denies sending troops into DR Congo.
Earlier, a recent Zimbabwean army deserter told the BBC he had been part of a force that remained in DR Congo after the end of the last war in 2003.
"There are about 250 soldiers who were left behind without knowledge of other countries," he said.
He said he had been on duty in Goma and the mining centre Lubumbashi, and soldiers were rotated about every six months.
Meanwhile, Britain's Financial Times newspaper said soldiers from the Rwandan army had been fighting alongside Gen Nkunda.
Their reporter in eastern DR Congo interviewed former rebels and observers who said some soldiers were continuing to receive their Rwandan salaries while fighting with the general.
Earlier this week a Rwandan presidential aide said it was possible demobilised Rwandan troops were involved. However, Kigali has repeatedly denied sending forces into DR Congo.
BBC Africa analyst Martin Plaut says similar statements were made during the early stages of the last war - and no-one doubts that foreign troops played a key role in that conflict.