U.K. authorities are punishing Rwanda over its support of the rebels who now control two major cities in eastern Congo.

Rwanda-backed rebels have reached the center of east Congo’s second-largest city, Bukavu, and taken control of the South Kivu province administrative office.

On February 16th soldiers from M 23 marched single-file through the streets of Bukavu, eastern Congo’s second-largest city. The beleaguered remains of the Congolese army had retreated without a fight. Rebel fighters toting grenade-launchers and machine-guns took triumphant selfies in the city’s main square.

Britain on Tuesday said it would pause some bilateral aid to Rwanda and impose other diplomatic sanctions on Kigali over its role in the conflict in neighbouring Congo, a move Kigali termed "punitive".