JUBA — Three aid volunteers working at Ebola screening points along the DR Congo border were killed in clashes in South Sudan, the International Organisation of Migration (IOM) said Wednesday.

"The IOM volunteers, one female and two males, were caught in a crossfire during clashes that broke out" on Sunday, in Morobo County in the Central Equatoria region, the UN agency said in a statement.

Two other male volunteers were injured, while a female volunteer and the son of the woman who was killed were abducted.

"We are deeply saddened by the loss of our colleagues and we extend our heartfelt condolences to their families and friends," said IOM chief of mission in South Sudan, Jean-Philippe Chauzy.

According to the statement, the IOM has suspended screening for Ebola at five sites along the border with the Democratic Republic of Congo.

An Ebola outbreak has killed more than 2,000 people in DR Congo since Aug. 2018, placing the region on high alert, with cases already having spread to Uganda.

"The safety of our personnel is paramount and will not be further jeopardized until we secure guarantees for the security of all our personnel operating in Morobo County," said Chauzy.

The UN's humanitarian agency OCHA also condemned the killings in a statement, noting it was the first reported killing of aid workers in South Sudan since 2018.

At least 115 aid workers, mainly South Sudanese, have been killed since the country plunged into conflict in December 2013 after President Salva Kiir accused his former deputy Riek Machar of plotting a coup against him.

The conflict has left nearly 400,000 dead and displaced millions.

A peace deal was signed in September last year and a ceasefire has largely held, but fighting in the Central Equatoria region has continued between government forces and a holdout rebel group.

A long-delayed unity government is due to be formed by Nov. 12, however Machar is seeking further postponement over crucial outstanding issues. — AFP