Suspected fighters from M23, a rebel group that claimed large swaths of territory between 2012 and 2013 has seized at least two villages overnight in the eastern Democratic Republic of the Congo (DRC) near the border with Uganda and Rwanda, according to local officials.

On Monday, Lieutenant-Colonel Muhindo Luanzo, assistant to the administrator of Rutshuru Territory, blamed the attack on fighters from M23, a rebel group that seized large swaths of territory in 2012 and 2013.

The two villages, Tshanzu and Runyoni, were the last redoubts of M23 before they were chased by Congolese and United Nations forces into Uganda and Rwanda in 2013.

Since then, there have been regional efforts to demobilise the fighters, but the group has complained about the slow implementation of a peace accord and some have returned to the DRC.

It was not immediately possible to confirm the identity of the armed men who took over the two villages.

Luanzo said the gunmen stormed Tshanzu and Runyoni simultaneously late on Sunday night.

“Now our troops are conducting counterattack operations because, during the night, they identified the enemy coming from Rwanda,” Luanzo told Reuters news agency by telephone.

UN investigators have accused Rwanda and Uganda, which intervened militarily in the DRC during two regional wars two decades ago, of supporting M23. The two countries deny this.

Al Jazeera shared that some of the people fleeing the affected area claim to have recognised some of the commanders of the M23 group – which has been accused of rights abuses.

“Hundreds of people have crossed through the town of Bunagana,” according to Malcolm Webb, an Al Jazeera reporter.

On Sunday evening, the United States issued a security alert, warning of a potential attack on the provincial capital of Goma, which is about 50km (31 miles) to the southwest of the two villages, and advising its personnel to shelter in place.