UNHCR says violence following last month’s contested presidential election caused some 50,000 to flee across Ubangi river into the DRC.
The number of people fleeing violence in the Central African Republic has doubled in just a week to nearly 60,000, according to the UN refugee agency, as post-electoral violence intensifies.
CAR's government has been battling rebel groups seeking to overturn a December 27 vote in which President Faustin-Archange Touadera was declared victor despite fraud claims.
"What's clear is the situation has...worsened," UNHCR spokesman Boris Cheshirkov told a UN briefing in Geneva.
"What we are hearing from (refugees) is some of them have been separated from loved ones, some have had loved ones killed, that the attacks have intensified," he added.
The UN refugee agency UNHCR said more than 50,000 of those had fled across the Ubangi River to the Democratic Republic of Congo – with 10,000 people arriving in the DRC on Wednesday alone as rebels attacked near the CAR capital Bangui.
Others have arrived in Cameroon, Chad and the Republic of Congo.
Cheshirkov said access to many in the Democratic Republic of Congo was difficult and that the agency was seeking to mobilise more resources and arrange for the airlift of supplies.
The Norwegian Refugee Council also said on Friday that the unrest had caused disruptions to aid delivery, cutting off humanitarian aid to 2.8 million people in the former French colony.
Attack near capital
Landlocked CAR is one of the world's poorest nations and has seen a string of coups and wars since it gained independence from France in 1960.
On Wednesday, rebel forces in the CAR mounted their closest attack yet to Bangui – which lies on the Ubangi river across from the DRC – before being pushed back with the loss of a peacekeeper, the UN said.
Rebels launched an offensive vowing to march on the capital ahead of the contested December 27 presidential election, in what the government has called an attempted coup.
On January 4, Touadera was declared victor of the ballot, although the CAR's political opposition cried foul.
The results account for only about half of registered voters, as hundreds of thousands were unable to cast their vote in areas held by rebels.
The Refugee Agency said it was already seeking $151.5 million this year to respond to the situation in the CAR.
However, given the needs of those fleeing their homes, UNHCR expects it will soon face a substantial shortfall, and called on the international community to expand its support.
"UNHCR and its partners are scaling up assistance for the new arrivals, despite poor infrastructure hampering the humanitarian response," said Cheshirkov.