WASHINGTON - For just the second time since the war began, the US Army is sending large units back to Iraq without giving them at least a year at home, defense officials said Monday. The move signaled how stretched the US fighting force has become.

A combat brigade from New York and a Texas headquarters unit will return to Iraq this summer in order to maintain through August the military buildup President Bush announced earlier this year. Overall, the Pentagon announced, 7,000 troops will be going to Iraq in the coming months as part of the effort to keep 20 brigades in the country to help bolster the Baghdad security plan. A brigade is roughly 3,000 soldiers.

The Army will try not to shorten the troops' US time, "but in this case we had to," said a senior Army official, who requested anonymity because of the sensitivity of the issue. "Obviously right now the Army is stretched," the official said.

The 4th Infantry Division headquarters unit from Fort Hood, Texas, will return to Iraq after a little more than seven months at home - the largest departure to date from the Army's goal of giving units at least a year's rest after every year deployed. The 1st Brigade of the 10th Mountain Division, based at Ft. Drum, N.Y., will go back to Iraq after just 10 1/2 months at home.

The only other major unit to spend less than one year at home was the Georgia-based 3rd Brigade of the 3rd Infantry Division, which returned to Iraq 48 days short of a year and is there now, according to the Army.

Pentagon spokesman Bryan Whitman acknowledged that the Texas unit's 81 day shortfall in rest time, "is not insignificant."

"There's only so many division headquarters," he said. "It reflects that this is a military that is in conflict. We're obviously using a significant portion of the combat units of the force. And it's a reflection of the realities that exist right now."

Whitman said the latest deployment orders released Monday would also require the Hawaii-based 25th Infantry Division Headquarters unit to stay in Iraq for about 46 days longer than its planned year.

Defense officials and military leaders disagreed last week over how long it will take to determine if the latest buildup - which added five brigades to what had been a fairly consistent level of 15 brigades in Iraq - is working.

Maj. Gen. William B. Caldwell, the military's chief spokesman in Iraq, said commanders won't know until at least autumn when they can begin to bring troop levels back down. A day later Defense Secretary Robert Gates told a congressional committee that he was disturbed to hear that comment, and he said commanders should be able to make the evaluation by summer.

So far two of the five Army brigades planned for the buildup are in Baghdad, and a third is moving in now. All five will be there in June.

The Army's stated goal is to give active-duty soldiers two years at home between overseas combat tours. But that has been largely impossible because the Army does not have enough brigades to meet the demands of simultaneous wars in Iraq and Afghanistan. The latest buildup increased the demands, but until recently the Army had been able to give units at least a year break.

Military leaders say the 12 months are needed so the units can rest and then become adequately trained and equipped to go back.

Throughout the war, some smaller, more specialized units have had to deploy without 12 months rest. The Pentagon is currently developing a policy that would provide additional pay to units that don't get the year break.

Other deployments announced Monday include:

-- The 18th Airborne Corps Headquarters unit, based at Fort Bragg, N.C., will go to Iraq in November

-- The 1st Armored Division Headquarters, based in Wiesbaden, Germany, will go in August

In addition to the 7,000 newly announced deployments, Whitman said about 2,000 military police have gotten their orders to go to Iraq. Gates announced last month that commanders requested about 2,200 military police. About 200 were already there and had their tours extended to meet the request, according to the Army.

Also, the 2nd Brigade, 82nd Airborne Division from Fort Bragg, which is currently in Iraq, will serve a full year there and return home in January 2008 rather than in September as originally planned.