At least 14 United Nations peacekeepers have been killed and at least 53 more wounded in an attack in eastern Democratic Republic of Congo, UN officials have said.
A UN official had earlier acknowledged that a "large number" of UN peacekeepers were killed or wounded in the attack in the North Kivu province late last night.
Five Congolese soldiers were killed in addition to the 14 peacekeepers killed in the attack, to which the UN mission say they are coordinating a joint response with the Congolese army.
The attack occurred in Congo's North Kivu province, which has remained a hotbed of armed militias, who continue to battle for control over the mineral-rich countryside despite the end of a major war over a decade and a half ago.
Gilbert Kambale, the president of an activist group in Beni, said the UN soldiers targeted in the attack were Tanzanian. A UN official confirmed that information.
Mr Kambale said the attack occurred about 50 km northeast of Beni city on the road that leads to the Uganda border, near where militants killed at least 26 people in an ambush in October.
Established in 2010, MONUSCO, the United Nations's largest peacekeeping mission, has recorded 93 fatalities of military, police and civilian personnel.
"Our thoughts and prayers with families and our colleagues in MONUSCO (peacekeeping mission)," Jean-Pierre Lacroix, Under-Secretary-General for Peacekeeping said.
He added: "Reinforcements are on scene and medical evacuations by mission are ongoing."
UN Secretary General Antonio Guterres said it was the worst attack on UN peacekeepers in the organisation's recent history.
In a statement, Mr Guterres said: "I condemn this attack unequivocally. These deliberate attacks against UN peacekeepers are unacceptable and constitute a war crime.
"I call on the DRC authorities to investigate this incident and swiftly bring the perpetrators to justice. There must be no impunity for such assaults, here or anywhere else."