United Nations helicopters have failed to stop rebels from taking control of another town in the eastern Democratic Republic of Congo.
A U.N. spokesman said that rebels from the M23 group fought government troops on Saturday and captured the town of Kibumba, about 30 kilometers north of Goma, the capital of restive North Kivu province.
Thousands of civilians fled the area, amid concerns that the rebels might try to take Goma itself.
Renewed fighting between the rebels and Congolese soldiers erupted Thursday, with the two sides blaming each other for starting the violence.
The U.N. peacekeeping mission, MONUSCO, said the M23 had launched the offensive with heavy weapons early Saturday. But he could not confirm Kinshasa's accusations that thousands of Rwandans had entered Congo to support the rebels.
A U.N. peacekeeping spokesman said that U.N. Secretary-General Ban Ki-moon spoke with Rwandan President Paul Kagame urging him to use his influence on the M23 to help calm the situation.
Most members of M23 group are former Congolese soldiers who defected earlier this year, demanding better pay and weapons.
The United Nations Security Council has held a closed-door emergency meeting Saturday at France's request to discuss the matter.
The renewed violence coincides with the release of a United Nations report on the conflict that repeats earlier accusations that elements in neighboring Rwanda and Uganda are supporting the rebels.
Rwanda and Uganda have strongly denied accusations they are supporting the M23. Uganda has said if the United Nations does not withdraw the allegations, it may remove its soldiers from international peacekeeping missions, including the one in Somalia.