BAGHDAD, June 26, 2005 — Faced with a ballooning prison population, U.S. commanders in Iraq are building new detention facilities at the notorious Abu Ghraib prison and Camp Bucca near the Kuwaiti border and are developing a third major prison, in northern Iraq.

The burgeoning number of detainees has also resulted in a lengthy delay in plans for the U.S. to transfer full control of Abu Ghraib to the Iraqi government.

Maj. Gen. William Brandenburg, who oversees U.S.-run prisons in Iraq, had planned to be out of Abu Ghraib by early spring. "I believed it until mid-December, but the numbers just weren't going that way," he said. "Business is booming."

The new timeline calls for the U.S. to stop using Abu Ghraib by February, at which point the entire prison would be turned over to the Iraqi Ministry of Justice.

After the scandal over abuse of Iraqi prisoners by U.S. soldiers, President Bush had advocated demolishing Abu Ghraib "as a fitting symbol of Iraq's new beginning."

But the Iraqi government has begun using the prison, which was a notorious torture center under Saddam Hussein, to house prisoners convicted under its nascent criminal justice system. The prison, just west of Baghdad, is currently a joint facility, with the U.S. Army and the Iraqi government housing detainees in separate compounds.

Aggressive operations against insurgents over the last six months have brought a flood of prisoners to U.S.-run facilities — including many believed to be hard-line rebels who have attacked American troops.

The number of prisoners held by the U.S. in Iraq reached record levels this month before falling slightly. As of Saturday, the average prisoner total in June stood at 10,783, up from 7,837 in January and 5,435 in June 2004.

The two main U.S. Army-run prisons, Abu Ghraib and Camp Bucca, are operating near their maximum or "surge" emergency limits. On Saturday, the two prisons together held 10,178 inmates, with 1,630 detainees awaiting processing in different Army divisional and brigade headquarters.

"We're pushing our surge capacity," said Army spokesman Lt. Col. Guy Rudisill in Baghdad.

The Army is expanding both sites and working on the third major prison, near Sulaymaniya, which would house up to 2,000 prisoners; the additions will increase the total U.S. long-term detention capability to more than 16,000 prisoners.

Both Abu Ghraib and Camp Bucca are considered volatile facilities where guards must be on constant lookout for potential riots and escape attempts. The detention of the Iraqis is among the most controversial U.S. practices in Iraq, triggering daily demands for the release of most prisoners from Iraqi lawmakers, clerics and community leaders.

The potential effect of the crowding on both prisoners and guards could become a serious concern as Iraq moves into the heart of a broiling summer.

High stress among overworked U.S. military police is partially blamed for leading to the mistreatment of Iraqi prisoners last year that made Abu Ghraib synonymous to many Iraqis with U.S. abuse. And in April, 44 troops were injured when insurgents launched a well-planned attack on Abu Ghraib, apparently aimed at freeing prisoners.

At Bucca, meanwhile, officials have witnessed a spate of escape attempts and at least two major riots in the last six months.

"It's been a challenge," said Col. James B. Brown, commander of the 18th Military Police Brigade. "Many of the people we've now captured have not given up the struggle."

Brown has reassigned MPs from other duties in Iraq, including training new Iraqi police officers, to help beef up the forces at Bucca and Abu Ghraib.

Brandenburg emphasized that he hoped to end the U.S. presence at Abu Ghraib by early next year. But with a large percentage of the detainees taken into custody in and around the capital, the general estimates he will still need the capacity to hold about 2,000 prisoners in the Baghdad area.

As a result, the eventual Abu Ghraib hand-over will coincide with an expansion of the Camp Cropper prison, which is on a U.S. base near Baghdad's international airport and houses "high value" prisoners such as Hussein and his top lieutenants.

Abu Ghraib was within 100 prisoners of its 3,500 surge limit when a new 400-person compound was completed on June 15 on the prison grounds. A second compound should open on July 20, Rudisill said.

As of June 20, Bucca's population stood at 6,450 prisoners, just 50 below its limit. Brandenburg plans to add space for 1,400 more prisoners by November.

The newest U.S.-run prison will be Ft. Suse, a former Russian-built barracks near Sulaymaniya.

"Part of it used to be a prison, so it should be easy to renovate," Brandenburg said.

The expansion campaign will cost more than $50 million: $30 million for Camp Cropper, $12 million to expand Camp Bucca, $8 million to renovate Ft. Suse and less than $1 million for Abu Ghraib.

Efforts to relieve the prison crowding by speeding up releases have been frustrated, officials say, by an increase in detainees deemed a high risk to commit acts of violence if set free. A Combined Review and Release Board of three U.S. officials and six Iraqis — two each from the ministries of interior, justice and human rights — reviews each prisoner within 90 days of arrival.

The board decides which prisoners can be released and which pose an immediate threat and must be detained. Rudisill, the Army spokesman, said the criteria include: the quality of the evidence against the prisoner; capabilities such as military training or electrical skills that could be put toward making bombs; suspected connections to insurgent cells; and "expressed philosophy."

Those judged too dangerous to be released can be held indefinitely with reviews every six months under the United Nations Security Council resolution that gave coalition forces the authority to maintain order in Iraq. About 1,600 detainees have so far been routed through the Iraqi justice system.

A second joint Iraqi-U.S. review board has been created in hopes of speeding up prisoner releases. But an increase in alleged hard-core detainees has partially stymied the process. Through the end of last year, Rudisill said, about 40% of the detainees who were reviewed were judged "high risk" or "extremely high risk." Since January, that percentage has risen to 60%.

"We're holding on to more and more of them," Rudisill said. "Since the beginning of the year it's kind of flip-flopped."

The crunch has led to a constant state of alert at Camp Bucca, where guards have struggled to contain repeated escape attempts and what Brown called "several large-scale uprisings." The camp is a grid of fenced-in indoor enclosures, each housing up to 800 prisoners. As the population rises, commanders plan to gradually shift to smaller, easier-to-control compounds.

Captured foreign fighters are kept in a separate compound, but Rudisill said they numbered fewer than 400.

Bucca faces constant escape attempts because its soft sand is ideal for tunneling, unlike at Abu Ghraib. Frequent fog and sandstorms at Bucca also reduce visibility to near zero, allowing escapees to rip seams in the double line of fencing.

One tunnel was discovered when a truck tire broke through its roof, and guards have discovered others by spotting prisoners trying to discard the excess sand. No one has escaped through a tunnel, but 11 prisoners did reach freedom through a hole in the fence in May. All were recaptured within a day, Brown said.

Violence has also been a persistent problem at the volatile U.S. lockups, where prisoners fashion knives from plundered metal and craft other home-made weapons.

On Jan. 31, the day after Iraq's landmark parliamentary elections, guards used live ammunition to put down a riot among prisoners apparently outraged about the alleged desecration of Korans by the U.S. military; four inmates died. A subsequent U.S. investigation showed no military mishandling of the Koran at Bucca, officials said.

April saw a pair of violent incidents. One centered around a fight between rival factions in a compound that left one prisoner dead.

The second was an uprising in which 12 inmates were injured and one of the senior camp commanders was hit by a rock and suffered a shattered cheekbone and two lost teeth.

Rioters have used slings to throw stones so hard that some have shattered the guard tower glass and been embedded in the wall. Other prisoners have ignited socks soaked in flammable hand sanitizer and stuffed with sand and excrement to create what Brown called "quite a disgusting incendiary device."

Investigations have revealed a disturbing level of coordination and communication between incarcerated insurgents and those on the outside, officials say.

For example, the Jan. 31 riot, Brown said, was believed to be "linked to a larger campaign timed to steal headlines from the [Iraqi national] elections."