| GISENYI, Rwanda
GISENYI, Rwanda Olive Kukamujeni does not know what fate met two of her children when a gun battle between Congolese troops and fighters loyal to a renegade general erupted in her home village.
"The fighting was so hard, everybody ran," Kukamujeni told Reuters at the border with Rwanda, exhausted by her ordeal. "I don't know if they died or not."
Five months pregnant and with another child strapped to her back as she awaited transport to a nearby camp, Kukamujeni is among 3,500 people who have fled the Masisi region in Congo's North Kivu province since fighting broke out there on Sunday.
The violence has left the U.N. refugee agency (UNHCR) in Rwanda scrambling to cope with the unexpected wave of displaced people, exacerbating a humanitarian situation already made difficult by bouts of fighting among rebel groups. The agency is working to expand the capacity of an overstretched transit camp, while a Rwandan official said another centre might be needed if the number of refugees continued rising.
Kinshasa is on the hunt for Bosco Ntaganda, a former rebel commander who fought the government before he was integrated into the army alongside other militants in a 2009 peace deal.
Clashes erupted after Congolese President Joseph Kabila announced last month he would try to arrest Ntaganda, accused by the International Criminal Court of recruiting child soldiers to fight in northeastern Congo's ethnic conflict.
Kabila had previously said Ntaganda was a lynchpin in the fragile peace deal that integrated his fighters. The region remains plagued by myriad rebel groups after a 1998-2003 war.
Ntaganda denies committing war crimes, and hundreds of soldiers loyal to him have defected from the armed forces in the past few weeks.
Refugees said government soldiers had been flooding into their villages in the Masisi region, Ntaganda's home turf. The U.N. peacekeeping mission in Congo, MONUSCO, has deployed troops there in a bid to protect the civilian population.
"Many people died. I saw wounded government soldiers and civilian bodies," said a refugee, Felicite Mukarego. "That's why we ran."
After two days of heavy fighting in her hometown of Gicanga, Mukarego grabbed three of her children and trudged through forest for 72 hours to seek refuge in Rwanda. She ended up at UNHCR's Nkamira transit camp, 22 km (14 miles) south of the Gisenyi border crossing.
Mukarego's husband, who followed her two days later, told her Ntaganda's soldiers had seized Gicanga as government forces deserted the town.
It was not possible to independently verify the account, but a senior military source told Reuters earlier this week the dissident forces had taken control of some territory in Masisi.
The UNHCR said that, by mid-2011, it was assisting some 56,000 people of concern in Rwanda, mainly refugees from the Democratic Republic of the Congo. The agency already operates three refugee camps and several transit camps in the country.
But it may not be enough.
As a thick mist rolled off the hills backing onto the Nkamira camp, U.N. employees worked to repair a number of large plastic-walled tents to raise the centre's capacity beyond its 2,700 people limit.
"We're working on rehabilitating some shelters so that we may accommodate up to 5,000," said Anouck Bronee, a UNHCR spokeswoman.
Rwanda's director of refugee affairs, Jean Claude Rwahama, told Reuters as he surveyed the camp that "if the numbers continue to increase, we'll need to have another place."
Amnesty International on Thursday urged the warring factions not to launch indiscriminate attacks nor enlist child combatants.
"All parties to the conflict must ensure that civilians are not caught in the crossfire," the human rights watchdog said.
(Writing by Richard Lough; Editing by David Clarke and Alessandra Rizzo)