AFP/ Geneva

Surging violence in the Central African Republic has forced tens of thousands to flee their homes in recent weeks to escape killings, rape and pillaging by militias, the United Nations said on Tuesday.

Since the beginning of the year, some 30,000 people have left their homes and found refuge within CAR, while more than 20,000 others have flooded into neighbouring Democratic Republic of Congo since December, the UN refugee agency UNHCR said.

"There is just total lawlessness, and the civilian population is being caught in the middle," agency spokeswoman Karin de Gruijl told reporters in Geneva.

The exodus is only the latest example of the instability and violence that has long rocked CAR.

The country is still struggling to recover from the 2013 coup that ousted president Francois Bozize and which pushed it into a conflict that took on an unprecedented religious dimension, pitting the country's Christian and Muslim populations against one another.

Largely "anti-balaka" -- or anti-machete -- militias have been formed to avenge atrocities by the mostly Seleka rebels who were behind the March 2013 coup.

Both sides are accused by human rights monitors of serious abuses, including killings, rape and pillaging.

The most recent violence has been associated with seasonal movements of livestock and clashes between herders, local farmers and the anti-balaka, de Gruijl said.

Making things worse, "some herders have turned to ex-Seleka militias for protection," she said.

- Missing girls -

Recent military operations against ex-Seleka in the eastern mining town of Bria has also prompted deadly reprisal attacks by the guerillas on nearby villages.

"Civilian populations were caught in the middle and saw their villages, houses and belongings burned," de Gruijl said.

More than 19,000 refugees have flooded across the border to DR Congo from CAR's Kouango district since December, UNHCR said.

"They say that their houses are being burned and they have no other choice than to flee," de Gruijl said, pointing out that if they stay, "they risk being tortured or killed and women are being raped."

Since February 15, some 2,400 refugees -- most of them children -- have meanwhile crossed into DR Congo from Mobayi in CAR's north, ahead of expected violence by ex-Seleka after the military operation in Bria, de Gruijl said.

UNHCR teams are meanwhile receiving "alarming reports of sexual violence" by militias, including of three refugee girls kidnapped from the border area in DR Congo and taken back to CAR, she said.

"One girl who managed to escape told us that they were raped... The other girls are still missing," de Gruijl said.

"We fear that there are many more cases that remain unreported," she added, stressing the need to move refugees in DR Congo further away from the border area.

In total, more than 873,000 people have been displaced by violence in CAR, mainly since December 2013, around half of them living as refugees in neighbouring Cameroon, Chad, DR Congo and Republic of Congo, according to UNHCR.