Gert Rosenthal, the Guatemalan ambassador to the United Nations, called on all outside support for the rebel March 23 Movement to end "immediately."
"The Security Council expresses deep concern at reports indicating that such support continues to be provided to the M23 by neighboring countries," he said in a statement.
Guatemala holds the rotating presidency of the U.N. Security Council.
The Rwandan government was suspected of backing M23, which consists of former DRC soldiers who mutinied in April. M23 leader Bosco Ntaganda is wanted for war crimes that include the alleged conscription of child soldiers.
The Security Council, in a statement, said it was ready to apply sanctions to M23 leaders and those parties seen as violating an arms embargo against the group.
The U.N. Organization Stabilization Mission in DRC said six peacekeepers and an interpreter were wounded when they came under attack after returning from North Kivu province in mid-October. The mission described the attack as "premeditated."