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.

M23 and government. forces. Zones occupied. by M23. 200 km. kinshasa. Rwanda. Lake Kivu. Map data: OSM, NASA. Sources: military and humanitari

Rwanda, which diplomats say backs M23 fighters who seized Goma in Democratic Republic of Congo this week, called on Wednesday for a ceasefire across eastern Congo and for Congo to negotiate with the rebels while denying Rwandan troops were involved.

Their fury is focused on Rwandan President Paul Kagame, who they accuse of backing the rebels - an accusation long made by the UN. To put it bluntly, a group of UN experts maintains the Rwandan army is in "de facto control of M23 operations",

By Yassin Kombi and Sonia Rolley GOMA, Democratic Republic of Congo (Reuters) - Rwandan-backed rebels strengthened their control over east Congo's largest city, Goma, on Wednesday as columns of Romanian mercenaries hired to fight for Congo entered Rwanda under tight supervision by Rwandan security forces.