Most of the inmates are linked to the 1994 genocide, which according to the UN estimates, claimed lives of about 800,000 ethnic Tutsis and moderate Hutus.
According to the progovernmental daily New Times, Gisenyi prison can only accommodate 2,000 inmates but almost twice the number are currently held there.
"We took the decision because the place is congested and it has compromised sanitation standards," New Times quoted as saying Pierre Celestin Twagirayezu, Rubavu District Mayor. "Transferred are those already convicted," he added.
Some of the inmates, who spoke to The New Times, welcomed the transfer.
© Hirondelle News Agency