Rebels in the Democratic Republic of Congo have seized another town after clashing with government troops backed by UN peacekeepers' helicopters.
The M23 fighters are said to be in a place called Monigi, 4km from Goma, increasing fears that they are advancing towards the oil-rich region's main city with the aim of capturing it.
The rebels said on Sunday that they have reached the "door" of Goma. "We're at the door... we are not in the city of Goma. It's not our ambition to take Goma. Nevertheless if (President Joseph) Kabila's army attacks us, we will pursue the enemy until it is repelled very far from Goma," Vianney Kazarama, a rebel spokesman, told the AFP news agency.
Al Jazeera's Nazanine Moshiri reporting from Nairobi, Kenya, also said that the rebels were "extremely close" to Goma.
"The rebels are actually 4km outside Goma. The airport is on that road...and if the rebels manage to take the airport, then Goma will fall to the rebels," she said.
The rebels' advancement came as the UN Security Council demanded an end to foreign support for the fighters.
Kinshasa, meanwhile, made fresh accusations against its eastern neighbour Rwanda, saying it was backing the rebel forces.
UN leader Ban Ki-moon has appealed to Rwanda's President Paul Kagame to "use his influence on M23" to end the rebellion, Herve Ladsous, the UN peacekeeping chief, said.
Rwanda has denied a report by UN experts that it has backed the rebels.
Ladsous said the United Nations could not confirm whether Rwanda is helping the new rebel offensive but told reporters that M23 "attacking forces are well-equipped and very well supplied."
UN urges end to violence
Saturday's Security Council statement demanded an end to the M23 advance and "that any and all outside support and supply of equipment to the M23, cease immediately."
It vowed new sanctions against M23 leaders and those who help it breach UN sanctions and an arms embargo.
The latest fighting has forced more than 7,000 people to flee to the already packed Kanyarucinya displaced persons' camp, some 10km outside Goma.
The DR Congo army said on Sunday that fighting between its troops and rebels has reached the refugee camp.
"The clashes are now occurring in Kanyarucinya camp. The enemy overtook on the right and all the displaced have left the camp and are apparently now in the city of Goma," an army intelligence colonel told the AFP news agency.
The fighting was just the latest clash this week between the army and the rebels of the M23 group, composed of ethnic Tutsi army mutineers.
While each side blamed the other for the latest violence, the UN's peacekeeping mission, MONUSCO, said the M23 had launched an offensive with heavy weapons early on Saturday.
As a result, the UN mission had deployed its peacekeepers to protect civilians.
"As part of this, 10 missions were carried out by (MONUSCO) attack helicopters," it said in a statement.
"MONUSCO firmly condemns the renewal of hostilities. It calls on the M23 to immediately halt its attacks, which have caused a deterioration of the already fragile security and humanitarian situation."
The attack helicopters, provided by Ukraine, were put on standby on Friday after the M23 attacked the army just north of Goma.
MONUSCO said the latest fighting was taking place about five kilometres from the Kanyarucinya camp, which currently holds between 60,000 and 80,000 displaced people.
The UN peacekeeping spokesman said government forces and MONUSCO peacekeepers "are attempting to hold off a possible M23 advance toward Goma at Kibati," about 20km to the north.
"As of right now, UN staff in Goma are gathering at security assembly points to ensure their protection," he said, adding that UN forces in the city and its airport are on "high alert".
The clashes are the most serious in the rebellion since July, when UN attack helicopters were last put into action against the M23.