Foreign Ministry official Yussef Mahmud on Friday told the Bahrain News Agency his ministry had asked its embassy in Washington to query US officials about the condition of Juma al-Dossary after a report by the Bahrain Centre for Human Rights (BCHR).
The Bahraini government wants the US to confirm or deny the report of torture suffered by al-Dossary, reported Aljazeera's correspondent.
The BCHR report, quoting three Britons recently freed from the US naval base in Cuba, said al-Dossary was repeatedly beaten by US soldiers, who slammed his face into the floor and broke his nose.
The Britons, young Muslims who were detained in Afghanistan in 2002, were the latest released detainees to allege abuse.
"The Bahrain embassy in Washington has been instructed ... to send an official memorandum to the US secretary of state to inquire about the reports ... on torturing a Bahraini national at the Guantanamo prison," Mahmud told the agency.
Al-Dossary is believed to be mentally ill. There are six Bahrainis, including al-Dossary, held in Guantanamo for more than two years without trial.
A group of international lawyers visited Bahrain, the headquarters for US Navy's Fifth Fleet, in July as part of a trip that took them to other Arab countries to prepare a lawsuit on behalf of the Guantanamo prisoners.