Thousands of people living near DR Congo's eastern border with Uganda fled their homes on Monday after suspected insurgents attacked army positions, officials said.
The attacks began at around 2300 EAT on Sunday with gunfire continuing into the night, sending desperate residents of Rutshuru territory in troubled North Kivu province fleeing over the border into Uganda.
The Congolese military pinned the blame for the attacks on an insurgent group called M23, one of more than 120 armed groups who roam the area, a legacy of regional wars that shook the area more than two decades ago.
The M23, a Congolese group largely defeated after launching a rebellion almost a decade ago, denied any involvement.
The attacks took place near Bunagana, a key border post and transit point for goods headed to regional capital Goma some 80 kilometres (50 miles) west.
The assailants overran the position of a paramilitary guard, stationed in the area to protect the Virunga National Park, a renowned conservation site.
Local officials and the Red Cross in the Kisoro region of Uganda said roughly 5,000 people had poured across the border and the area was "overwhelmed".
The escapees included older people, women and children, and they had no access to basic amenities like water or shelter, according to local official Rukundo Manasseh.
The arrivals were being taken to a transit centre in Nyakabande, said Kisoro Red Cross chief Primrose Natukunda.
State of siege
"The M23 insurgent movement attacked army positions... with the intention of carrying out other actions in the territory of Rutshuru," Brigadier General Sylvain Ekenge told reporters in Goma.
However, M23 leader Bertrand Bisimwa denied the claims, saying in a statement: "The M23 is not engaged in any armed confrontations in the territory of Rutshuru."
Congolese communication minister Patrick Muyaya earlier told Belgian media in Brussels that "several armed forces positions" had been attacked "in a strategic zone on the border between the DRC and Uganda".
The provinces of North Kivu and Ituri have been under a "state of siege" for months to support a military offensive aimed at neutralising armed groups.
President Felix Tshisekedi has replaced civilian authorities there with army and police officers.
M23 leader Bisimwa said rather than launching attacks, he was waiting "impatiently" for the implementation of commitments negotiated with Tshisekedi's government over a "definitive peace plan" in the east.
M23 fighters were integrated into the Congolese army under a 2009 peace deal but rebelled in 2012, claiming the deal had not been respected.
They briefly seized Goma but a year later they were defeated by a joint UN and Congolese army offensive.