BAGHDAD, Iraq – The American military said yesterday it plans to expand its prisons across Iraq to hold as many as 16,000 detainees, as the relentless insurgency shows no sign of letup one year after the transfer of sovereignty to Iraqi authorities.

The plans were announced on a day three U.S. Army soldiers were killed – two pilots whose helicopter crashed north of Baghdad and a soldier who was shot in the capital. At least four Iraqis died in a car bomb attack in the capital.

The prison population at three military complexes throughout the country – Abu Ghraib, Camp Bucca, and Camp Cropper – has nearly doubled to 10,002 from 5,435 in June 2004, Lieutenant Colonel Guy Rudisill, a spokesman for detainee operations in Iraq, said. Some 400 non-Iraqis are among the inmates, according to the military.

“We are past the normal capacity for both Abu Ghraib and Camp Bucca. We are at surge capacity,” Colonel Rudisill said. “We are not at normal capacity for Camp Cropper.”

The burgeoning prison population has forced the American military to begin renovations on existing facilities, and work has also begun on restoring an old Iraqi military barracks near Sulaimaniyah, 160 miles northeast of Baghdad. The facility, to be called Fort Suse, is expected to be completed by September 30 and will have room for 2,000 new detainees, Colonel Rudisill said.

All renovations should be done by February and are expected to make room for 16,000 detainees in Iraq, he said. Two weeks ago, the military completed a new 400-detainee compound at Abu Ghraib, which the American government sought to tear down after it became a symbol of an abuse scandal. It was kept in service after the Iraqi government objected. A new compound of the same size should be finished by the end of July at Abu Ghraib, Colonel Rudisill said.

The spokesman attributed the rise in the number of prisoners to “successful ongoing military operations against the insurgency and terrorists.”

Those operations, however, have not stemmed the daily carnage demoralizing the country of 26 million people. With the Sunni Arab-dominated insurgency targeting the Shiite majority, the wave of killings has slowly been pushing the country toward civil war.

Dozens of foreign fighters have been reported killed in American-led offensives in recent months, including Operation Spear at the porous Syrian border last week, but the deaths have had little effect on the resolve and ability of suicide bombers to strike at will.

Al Qaeda in Iraq, headed by Jordanian-born extremist Abu Musab al-Zarqawi, has claimed responsibility for many of the attacks carried out by such fighters, but there are other insurgent groups – including homegrown factions.

Yesterday, the American military raised the death toll in last week’s Fallujah attack to six, announcing that three female service members were killed in the ambush on an American convoy.

At least 1,740 members of the U.S. military have died since the beginning of the Iraq war in March 2003, according to an Associated Press count. At least 1,334 died as a result of hostile action. The figures include five military civilians.

There have been positive developments in the year since the June 28, 2004, handover – the most notable being the election of the 275-member National Assembly on January 30, Iraq’s first free vote in a half-century.