The head of the United Nations humanitarian arm today called for an investigation into reports that hundreds of people expelled from Angola and forced to cross the border into the Democratic Republic of the Congo (DRC) have been subjected to sexual violence, including rape.

"These allegations of abuse need to be investigated as a matter of urgency," said Valerie Amos, the Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator. "And every effort must be taken to prevent any further abuse," she added.

An estimated 7,000 people have arrived in DRC over the past two months after being expelled from Angola, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA), which noted that the UN first learned of the violations on 23 October from non-governmental organizations (NGOs).

According to protection officials with humanitarian organisations, some 6,621 people arrived in two areas of DRC's Western Kasai province in September and October, while NGOs in Bandundu province reported the arrival of another 322 people in the Tembo area.

Those arriving were reportedly illegal immigrants who had lived in Angola – most of them citizens of DRC – but there were some people from other African countries.

"We are seriously concerned by continuous reports of human rights abuses, including sexual violence," said Mohamed Boukry, Regional Representative of the Office of the UN High Commissioner for Refugees (UNHCR). "We call upon all parties to take all necessary measures to ensure the protection of affected populations in full respect of international human rights and humanitarian and refugee laws," he said.

Earlier this month, Margot Wallstr?m, the Secretary-General's Special Representative for Sexual Violence in Conflict, urged the national authorities in Angola and DRC to investigate the reports that women were raped during the expulsions.

"I expect the authorities of Angola and the DRC to respect human rights and to do everything in their power to prevent abuses of all kinds during any further expulsions," she stated.

OCHA said that, according to the results of a humanitarian assessment mission in Tembo, out of the 322 people expelled, 99 women and 15 men suffered sexual violence.

A preliminary report by aid workers said that more than 600 of those who went to Western Kasai also alleged that they suffered sexual violence. The claims are still being examined, and a humanitarian assessment mission is due to visit the area this week to look further into the allegations.

Expulsion of alleged illegal immigrants between Angola and the DRC happens often and has been linked to widespread poverty and lack of employment opportunities in the two countries, according to OCHA.

In October last year, tens of thousands of people were expelled in both directions, with many being stranded in border areas for days with little food and water and no shelter or proper sanitation.

"It is crucial for illegal immigrants to be able to transit in an orderly manner so that humanitarian problems can be prevented, including potential epidemics," said Fidèle Sarassoro, the UN Humanitarian Coordinator for the DRC.