The Democratic Forces for the Liberation of Rwanda (FDLR) have missed the deadline set by the Southern African Development Community to voluntarily disarm themselves, it said on Saturday.
In spite of the presence of 20,000 UN peacekeepers, around 50 Congolese and foreign armed groups are still active in the region.
SADC chairman President Jacob Zuma urged the FDLR to come forward and disarm themselves unconditionally.
“The deadline set by the heads of state and government of SADC… for the FDLR to disarm voluntarily or face military action expired yesterday, 2 January 2015,” Zuma said in a statement.
A joint summit by the SADC heads of states would be held in Luanda, Angola to decide on measures to be taken.
“SADC remains committed to the internationally mandated objective of neutralising all negative forces operating in the Democratic Republic of the Congo, including the FDLR, and remains ready to play its fullest part in this regard,” Zuma said.
The east of the DRC has been a conflict area for two decades, French news agency Agence France-Presse reported last month.
Two major wars between 1996 and 2003, were fought with neighbouring countries including Uganda and Rwanda intervening directly or using militias to do their bidding.