The three peacekeepers — one from Uruguay and two from South Africa — were killed over the weekend in the fighting around Goma. More than 300 U.N. peacekeepers have been killed since the mission in Congo was deployed in 1999. The deaths have renewed questions about the future of the U.N. mission, known as MONUSCO.

There are growing international calls for peace talks to end the escalation of violence in the east of the Democratic Republic of Congo. The fate of the economic and trading hub Goma is still unclear. UN officials have said the situation is chaotic with fighting continuing in parts of the city.

Rwanda's ally Uganda, unhappy about another rebel group in DR Congo that threatens its security, has also been accused of helping the M23 - with its officers also spotted at Tchanzu. The UN experts say Uganda has also supplied weapons, hosted rebel leaders and allowed cross-border movements of M23 fighters - accusations Kampala denies.

The United States urged the United Nations Security Council on Tuesday to consider measures to halt an offensive by Rwandan troops and M23 rebel forces in eastern Democratic Republic of Congo as a conflict there escalates.

Rwanda-backed fighters advanced on a second front in their offensive across eastern DR Congo on Wednesday after seizing control of most of the key city of Goma during heavy fighting

Rwanda-backed fighters controlled most of the besieged DR Congo city of Goma on Wednesday as residents slowly emerged from their homes after days of deadly fighting in the key mineral trading hub.The M23 armed group and Rwandan troops have seized the airport and most of the centre and neighbourhoods since marching into the eastern provincial capital on Sunday after a lightning offensive.