President Félix Tshisekedi sent Thomas Lubanga, Germain Katanga and Floribert Ndjabu to negotiate with Codeco militiamen who have been accused of multiple atrocities in recent months.

But a spokesman for the group told the French news agency that the Congolese army fired shells during the meeting, and the envoys had been seized. Attempts to reach them by phone have failed.

Codeco claims to represent the interests of the Lendu ethnic group in the fighting that has bedevilled eastern DR Congo for many years.

Lubanga and Katanga served prison sentences of 14 years and 12 years respectively after the International Criminal Court (ICC) found them guilty of committing war crimes in eastern DR Congo

Ndjabu was jailed for 15 years over the killing of nine UN peacekeepers.