A Romanian government institute tasked with investigating communist-era crimes has called for two former prison chiefs to be probed on suspicion of causing the deaths of 204 political prisoners.

The Institute for Investigating the Crimes of Communism gave the files, based on written testimonies and state archives, to the general prosecutors' office Thursday.

Institute chief Radu Preda said Marian Petrescu, commander of several labor colonies and prisons from 1956 to 1966, is suspected of running an abusive regime, leading to 104 deaths.

Gheorghe Bostina is suspected of causing the deaths of 100 prisoners from 1957-1960. The institute could not say where the two men were.

In 2013, the institute began investigating the deaths of thousands of political detainees. Two former prison commanders have been sentenced for crimes against humanity.