Baghdad: Iraqis are still being held illegally at a Baghdad prison that the government was supposed to have shut down in 2011 after allegations that detainees were tortured and abused there, Human Rights Watch said Tuesday.

The report by the New York-based rights group raises fresh concerns about the government's treatment of detainees after Iraqi authorities took over the country's prison system following the departure of U.S. troops last December.

Iraq's Human Rights Ministry has denied the Human Rights Watch claim as inaccurate, saying the detention centre in question, known by its former U.S. military designation as Camp Honor, was shuttered more than a year ago.

The prison is located inside the Green Zone in central Baghdad, which also houses government offices and foreign embassies.

The HRW report was based on interviews with 35 former detainees and their relatives and lawyers, as well as government officials who described ongoing interrogations at Camp Honor.

Hidden

"Iraqi security forces are grabbing people outside of the law, without trial or known charges, and hiding them away in incommunicado sites," said Joe Stork, Human Rights Watch's deputy Middle East director.

He called on Iraqi authorities to immediately release names of all detainees and where they are being held, and to release those who have not been formally charged.

Asked for comment, Human Rights Ministry spokesman Kamil Amin said Camp Honor "was closed more than a year ago."

'Not in use'

"All inmates were transferred to other prisons," Amin said. "We are confident that Camp Honor is not in use."

He denied that the government is running secret jails, and said all arrests and detentions follow legal standards.

The report said elite Iraqi troops controlled by Prime Minister Nouri Al Maliki are running two more secret jails in Baghdad where detainees are interrogated by judicial investigators.

The rights group also said it is withholding the identities of the people who were interviewed out of concern for their safety.