BAGHDAD — Sunni Muslims, many of them arrested with no warrant, were tortured in a secret Iraqi prison that Prime Minister Nouri al-Maliki has shut down, officials said.

Hundreds of Sunni men who were detained in October in Nineveh province — where al-Qaida in Iraq and other militant groups are dominant — were held for months in the secret facility, the Los Angeles Times reported Sunday. Many of them were routinely subjected to torture under the jurisdiction of Maliki’s military office until Iraqi human rights authorities were able to gain access to the prison, the newspaper said.

Provincial authorities in Nineveh alleged at the time of the sweeps that ordinary citizens had been caught up in sweeping arrests targeting militants.

Iraqi security officials, concerned about the possibility that courts would order those detained to be released, managed to obtain a court order to transfer the arrested Sunnis to the prison in Baghdad, the Times reported. They were held there until Iraq’s Human Rights Ministry inspected the prison.

Maliki said he would close the prison down and have its officers arrested, the Times said. Seventy-five of the arrested Sunnis have been released and 275 have been sent to conventional jails, officials said.

Inspectors concluded 431 people had been held at the facility and that more than 100 were tortured.

“There were a lot of marks on their bodies,” an Iraqi official familiar with the inspections said. “They beat people, they used electricity. They suffocated them with plastic bags, and different methods.”

Human rights officials said prisoners told them one of the prisoners — said to be a military officer under former dictator Saddam Hussein — died at the prison in January as a result of being tortured.