Mary Robinson, the special envoy of the UN secretary-general for the Great Lakes region, on Saturday \"strongly condemned\" an attack on a UN peacekeeping helicopter in the Democratic Republic of Congo (DRC), saying that such an attack is \"unacceptable.\" \"I learned with deep concern that a MONUSCO helicopter came under direct fire from positions held by the March 23 (M23) rebel movement in the Rumangabo region,\" Robinson said in a statement issued here, referring to the United Nations Organization Stabilization Mission in the DRC. Rumangabo, in the resource-rich but unstable province of North Kivu, is about 40 kilometers north of the provincial capital of Goma. It is near an important military base occupied by the rebel group. \"I strongly condemn this serious incident that threatens the security of MONUSCO personnel,\" said the statement. \"I wish to remind the M23 leadership that any act aimed at obstructing MONUSCO in the exercise of its mandate, as stipulated by the United Nations Security Council resolution 2098, is unacceptable.\" The rebel group, known as M23, is composed of a breakaway faction of soldiers from the DRC\'s national army. It seized seven towns in North Kivu province in eastern DRC in October 2012 and intensified attacks on schools, hospitals, homes and other civilian targets. The eastern province of North and South Kivu in DRC have witnessed increased fighting between government troops and the M23, which has displaced more than 100,000 people including many who have fled to neighboring Rwanda and Uganda.