The U.N. mission, in a release, expressed "deep concern" about the latest fighting that erupted after a group of M23 rebels attacked national forces Sunday in Mutaho, northwest of Goma.
"Any attempt by the M23 to advance toward Goma will be considered a direct threat to civilians," U.N. officials warned, noting its peacekeepers were prepared to take any necessary measures, including use of lethal force, to protect civilians.
Moustapha Soumare, the U.N. acting special representative in DRC, urged restraint to avoid an escalation.
"I call on all to abide by the Peace, Security and Cooperation Framework Agreement and to allow the political process towards peace to move forward," Soumare said, referring to the U.N.-brokered accord adopted in February.
Since March, tensions in the country have heightened, leading to the U.N. Security Council to authorize deployment of an intervention brigade within the mission to carry out targeted offensive operations against armed groups threatening the peace in eastern DRC.