M23 rebels launched an attack on troops on Sunday, in Bunagana, in the eastern Democratic Republic of Congo (DRC), which led to a heavy fight, according to officials.

Damien Sebusanane, the head of a local civilian group, said the majority of the population had fled the center of the town, which is a key transit point for goods on the Ugandan border.

Clashes renewed between M23 rebels and the army in the region, and the government has blamed neighboring Rwanda which has repeatedly denied supporting the rebel group.

On Sunday morning, the army was attacked in Bunagana and the nearby town of Tshengerero, both in North Kivu province, according to local military administrator Colonel Muhindi Lwanzo.

M23 fighters surrounded Bunagana, and Congolese army tanks fired at the rebels' positions from inside the town, Sebusanane said.

An army officer, who preferred to remain unnamed, told AFP that on Sunday afternoon, Congolese soldiers were pushing the rebels back, and fights were ongoing on the road leading from Bunagana.

The M23, a mainly Congolese Tutsi group of militants, is one of more than 120 other armed groups active in eastern DRC.

In 2012, a joint offensive by UN troops and the Congolese army put an end to the rebellion, but the M23 resumed fighting last year, accusing the government in Congo of not respecting a 2009 agreement under which its fighters were to be blended with the army.

Local sources reported in April that M23 rebels have taken control of several villages in eastern DR Congo after fighting with government troops in the Rutshuru region.

At the end of May, the DRC army confirmed that it was holding two Rwandan troops, a day after Kigali accused it of supporting the rebels who seized them.

Rwanda claimed that the two soldiers were kidnapped by a Hutu rebel group operating in eastern DRC. However, the DRC army, on the other hand, claimed the soldiers were trespassing on its territory and had been apprehended by civilians.

Relations between the DRC and Rwanda have been strained since the overwhelming entry of Rwandan Hutus suspected of slaying Tutsis during the 1994 Rwanda genocide in the eastern DRC.