BAGHDAD — An Iraqi security force under Prime Minister Nuri Kamal al-Maliki’s direct command held hundreds of detainees from northern Iraq in an undisclosed prison in Baghdad, torturing dozens of them, until the country’s human rights minister and the United States intervened late last month, Iraqi and American officials said.
Mr. Maliki ordered the prison closed and said he had been unaware it existed, according to the officials. His move brought the release of 71 detainees and the transfer of others to established prisons, but more than 200 remain in the place, on the grounds of the Old Muthanna military airfield, in northern Baghdad. All of the detainees were apparently Sunni Muslims.
American diplomats visited the prison on Wednesday, the officials said, and pressed Mr. Maliki’s government to investigate the circumstances of its creation and the treatment of detainees there, originally 431 in all.
In an interview, the minister of human rights, Wijdan Salim, praised Mr. Maliki for moving to close the prison and to order an investigation of what happened inside.
“He’s doing the best he can,” Ms. Salim said. “The problem we have is not with the prime minister, it’s with the judicial system.”
But the existence of the prison, first reported in The Los Angeles Times on Monday and widely repeated in the Iraqi media, enraged Sunni political leaders, who accused Mr. Maliki’s government of trampling the rule of law.
The disclosure bore striking similarities to the discovery of a secret underground prison in 2005 that had been operated by the police in Baghdad at the height of Iraq’s sectarian conflict.
Osama al-Najafi, a Sunni member of Parliament who is a leader of the electoral coalition that narrowly defeated Mr. Maliki’s bloc in last month’s election, said the existence of the prison was an example of “the dictatorship that has prevailed.”
“This secret prison has a sectarian character, and it shows that the security forces and the army have an iron fist outside of the framework of the Constitution,” he said.
Mr. Najafi represents Nineveh, the northern Iraqi province where the detainees were arrested last fall in a security sweep.
The detainees were transferred to the undisclosed prison on a judge’s order, Ms. Salim said, because of concerns that they would be released by sympathetic judges in the province. The prison, near two other known prisons operated by the Ministry of Defense, was called Nineveh Wall.
Mr. Najafi’s brother Atheel, the governor of Nineveh, said in a telephone interview that the arrests were carried out in October without warrants, which law requires. His public calls for an investigation at the time went unanswered.
The governor said he had spoken to some of the released detainees, most of whom reported torture and mistreatment. He said at least one detainee died while in the prison. Those released, he added, had been warned by prison officials not to discuss their treatment.
Two of them, reached by a correspondent for The New York Times in Mosul, Nineveh’s capital, refused to discuss their captivity.
Ms. Salim, who insisted on inspecting the prison after first hearing reports of a secret facility at Muthanna from relatives of those inside, said she witnessed evidence of brutality. “All of it is against human rights and the law,” she said.
Torture and other abuses of prisoners are pervasive in Iraq. The Ministry of Human Rights recorded 505 cases in 2009. The State Department’s annual human rights report, released last month, harshly criticized Iraq, particularly for the maltreatment of detainees before and after their arrests. “Allegations of abuse included beatings, sexual assault and death threats,” it said.
The senior American military spokesman in Iraq, Maj. Gen. Stephen R. Lanza, said that American officials had raised concerns about the prison with the Iraqi government.
“We believe the government of Iraq is aware of the need to conduct a thorough investigation of this incident and to ensure that those responsible are held accountable,” he said in a statement.
The public disclosure in this case could have political ramifications for Mr. Maliki. It comes at a crucial moment when he is trying to rally enough support after last month’s inconclusive election to ensure a second term as prime minister.
The prisoners were arrested by the Baghdad Brigade, a security force controlled by Mr. Maliki’s office, not by the military or the police. The prison was operated by the Baghdad Operations Command, which oversees security in the capital. A spokesman for the command did not respond to repeated requests for comments.
Both the brigade and the command have faced criticism in the past for acting outside the law and giving Mr. Maliki unconstitutional power.
Ms. Salim, who ran as a candidate with Mr. Maliki’s bloc, said that two judges and five investigators oversaw the detainees in the prison, giving their detention the veneer of legitimacy. Ms. Salim emphasized, however, that by law, all prisoners in Iraq, including those now held by the military and the police, should be held in prisons under the control of the Ministry of Justice. The transfer of prisoners is happening, though slowly.
It remained unclear whether other prisons like this existed elsewhere in Iraq. Ms. Salim said they did not, but the disclosure fueled the suspicions of Mr. Maliki’s critics. Governor Najafi said he believed that Iraq’s Second Army Division maintained secret prisons in Nineveh itself.