The Malawian military has announced that four of its soldiers serving in the UN peacekeeping mission in the Democratic Republic of Congo have been killed by rebels.

A spokesman said the soldiers were ambushed on Wednesday in an operation with their South African and Tanzanian colleagues.

He said other injured soldiers were receiving medical treatment.

The spokesman said it was not known which rebel group was responsible for the attack.

Several, including the Ugandan Allied Democratic Forces, are active in the east of the country.

The UN has raised the alarm over the escalation of fighting there, warning that the violence, which is unfolding alongside an Ebola outbreak, could hamper next month's elections.