Security forces are said to have raped over 650 girls and women on the Angola-DR Congo border [EPA]

More than 650 women and girls have been raped during mass expulsions from Angola to the Democratic Republic of Congo (DRC) in the past two months, according to a body of the United Nations.

Many of the victims said they were locked up and tortured for several weeks while they were raped repeatedly by security forces. 

The report by the UN Children's Fund (Unicef) said 6,621 people arrived in Congo's western Kasai province, in two waves during October. It is not clear on which side of the border the rapes took place.

"The conditions of expulsion are still terrible. In many cases, sexual violence is reported and even cases of torture," the report said, citing 657 instances of sexual violence based on evidence collated by welcome committees on both sides of the border.

Separately, the UN Office for the Coordination of Humanitarian Affairs (OCHA), citing humanitarian workers, said the true figure was close to 100.

"We are not in a position to confirm in which country they (the rapes) happened, but we do call on the authorities of the two countries to investigate these accusations to find out whether the rapes took place and where," Maurizio Giuliano, a spokesman of OCHA, said.

'No complaints'

Lambert Mende, the DRC information minister, said authorities had not received any reports of rape.

"We're not informed. We don't know, these figures are not confirmed," he said. "There are expulsions, perhaps there are rapes but we have received no complaints and we don't want to launch a dossier."

The report comes in the wake of an international outcry triggered by the rape of at least 303 civilians in eastern Congo between July 30 and August 3 by rebels in the town of Luvungi.

Angola and Congo often indulge in tit-for-tat expulsions and the figure touched 211,000 in 2009.

Angola helped the Congolese government fight off Rwandan- and Ugandan-backed rebels during fighting between 1998 and 2003, which drew in several neighbouring countries.

However, deteriorating relations between the two countries followed disputes over border demarcation, offshore oil ownership and closer Congolese relations with Rwanda and Uganda, its neighbours to the east.