UN Secretary-General Antonio Guterres strongly condemned on Tuesday violence targeting the United Nations in eastern Democratic Republic of Congo that killed three peacekeepers, a UN spokesperson said.

"He underscores that any attack directed against United Nations peacekeepers may constitute a war crime and calls upon the Congolese authorities to investigate these incidents and swiftly bring those responsible to justice," deputy UN spokesperson Farhan Haq said in a statement.

Guterres also said the United Nations would work with Congolese authorities to investigate the deaths of demonstrators.