BAGHDAD - Four prisoners with links to al Qaeda have escaped from the U.S.-controlled part of a maximum-security prison in Baghdad, U.S. and Iraqi officials said Thursday.

The breakout from Karkh Prison, formerly called Camp Cropper, is an embarrassment for the U.S. military, which has handed over control of all of the detention facilities it used to run to the Iraqi government. But at the request of the Iraqis, the U.S. has retained custody over some of the most dangerous prisoners, including those with ties to terrorist groups or Saddam Hussein's former regime.

An Iraqi military spokesman, Maj. Gen. Qassim al-Moussawi, told The Associated Press that the Americans informed them Thursday morning that four Iraqis being held by the U.S. had broken out of the prison, although it was not clear exactly when or how they escaped.

He said the men were linked to al Qaeda and facing the death penalty.

An American military spokesman, Col. Barry Johnson, confirmed there was an escape, but provided no details.

"We are working with Iraqi Security Forces to resolve this," he said. "Our first priority is recapturing the individuals involved."

On July 15, the U.S. military handed over about 1,500 prisoners to Iraqi authorities during the changing of the guard at Camp Cropper, but continued to hold onto some 200 detainees at the request of the Iraqi government. They are kept in a separate part of the prison dubbed Compound 5, and guarded by American soldiers.

Maj. Gen. Jerry Cannon, who is in charge of U.S. detainee centers in Iraq, previously described those prisoners who remain in the U.S custody as "former regime elements, al Qaeda operatives and very dangerous detainees." He said they would eventually be handed over to the Iraqi government before American forces pull out of the country entirely by the end of next year.

Thursday's escape is the second since the U.S. transferred custody of the detention facility to the Iraqis.

Just a week after the handover, four al Qaeda-linked detainees awaiting trial on terrorism charges escaped from the Iraqi section of the prison.

The $48-million complex has been used by U.S. forces since April 2003 and can hold up to 4,000 prisoners. It's now divided into six detainee compounds, and is manned by 700 Iraqi corrections officers and about 100 support staff.

The prison once held Saddam Hussein and other senior members of his regime.