M23 rebels in DR Congo (DRC) have seized the eastern border town of Bunagana on Monday, the militia members and local activists said.

In a statement, the rebels appealed to DRC President Felix Tshisekedi to "seize this opportunity to put an end to the violence caused by this useless war and to open direct negotiations with our movement."

But the Congolese army said the town had been taken by Rwanda because the rebels, allegedly supported by Rwanda, were suffering "enormous setbacks."

DR Congo has repeatedly accused Rwanda of backing the M23, whose leadership hails from the same Tutsi ethnic group as Rwandan President Paul Kagame.

"The Rwandan defense forces have this time decided to violate ... our territorial integrity by occupying the border town of Bunagana," the military said in a statement, describing the incident as "no less than invasion of the Democratic Republic of Congo."

Rwanda has not yet made any comments on the development, and has denied playing a role in any such recent attacks. Congo's government had broken off negotiations with the M23 in April this year. 

DRC soldiers, civilians flee to Uganda

Local activist said the Congolese army "has just given way" and was moving into Uganda, which borders both DRC and Rwanda.

"An army truck has just gone past, four jeeps and other vehicles which are full of soldiers," Damien Sebusanane, head of a civil society association, who was on Uganda's border with the DRC, told the AFP news agency.

Shaffiq Sekandi, Uganda's resident district commissioner for Kisoro district told Reuters that the fighting caused more than 30,000 Congolese asylum seekers and 137 Congolese soldiers to cross into Uganda on Monday.

"They are all over, the streets are full, others have gone to churches, they are under trees, everywhere. It's a really desperate situation," he said.

Dozens of police officers were also said to have surrendered to Ugandan troops.

The United Nations and African Union have voiced alarm about violence the region.

The UN had previously said that 25,000 people fled the violence on Sunday.

African Union Commission Chair Moussa Faki Mahamat called for an immediate cessation of hostilities and for talks between DR Congo and Rwanda.

Conflict between Rwanda and DR Congo

Tensions have risen between the two neighboring countries in recent weeks, with accusations of strikes rife on both sides.

Conflicts in the region in the 1990s and 2000s, and disease and hunger have led to thousands of deaths in the region. 

 The M23, a primarily Congolese Tutsi militia, is one of more than 120 armed groups active in eastern DRC. It briefly captured Goma in 2012, but a joint offensive by UN troops and the Congolese army quelled the rebellion.

Rwanda denies supporting the M23. It accuses Congo of collaborating with another militia group, the FDLR, founded by ethnic Hutus who fled Rwanda after participating in the 1994 genocide. Congo denies this charge.

tg/dj (AFP, AP, Reuters)