* U.S. Army to grow by up to 22,000 soldiers for 3 years
* Increase intended to ease strain of two wars
* Initial $1.1 billion cost won’t require new funding (Adds cost estimate and fresh quote in paragraphs 6 and 7)
By David Morgan
WASHINGTON, July 20 (Reuters) - U.S. Defense Secretary Robert Gates on Monday announced a temporary increase in the size of the U.S. Army that would boost the force by up to 22,000 troops for three years.
He told reporters at a news briefing that the increase, intended to cope with strains from the wars in Afghanistan and Iraq, would raise the total strength of the Army to 569,000 soldiers.
"The Army faces a period where its ability to deploy combat units at acceptable fill rates is at risk," Gates told reporters. "This is a temporary challenge which will peak in the coming year and abate over the course of the next three years."
The increase is smaller than a plan backed by Senator Joseph Lieberman, a Connecticut independent who sits on the Senate Armed Services Committee, which would have added about 30,000 troops to active duty.
The expansion was recommended by the Army’s civilian and uniformed leadership and strongly backed by President Barack Obama, Gates said.
The Pentagon plans to absorb an initial expansion cost of $1.1 billion through fiscal year 2010, which begins Oct. 1, without additional funding from Congress. But Gates suggested more funds could be necessary in fiscal years 2011 and 2012.
"These additional forces will be used to ensure that our deploying units are properly manned and not to create new combat formations," he said.
Gates authorized a permanent increase in U.S. Army strength soon after he became defense secretary in 2006, believing the largest branch of the U.S. military did not have enough forces to support heightened operations in Iraq and Afghanistan.
That increase, which was recently completed, boosted the Army’s size by 65,000 soldiers to 547,000. It also added 27,000 Marines to the U.S. Marine Corps.
MORE ‘DWELL TIME’
Gates’ decision to authorize a temporary increase comes as the U.S. military shifts its focus from Iraq to Afghanistan, where the number of U.S. troops is expected to reach 68,000 this year from about 32,000 at the end of 2008.
There are currently about 58,000 U.S. troops in Afghanistan and 130,000 in Iraq.
U.S. plans in Iraq call for a force reduction to between 35,000 and 50,000 troops by August 2010 and a complete withdrawal of U.S. forces by the end of 2011.
But Gates said the ongoing pace of Army operations, combined with changes in personnel policy, required a bigger force.
"The persistent pace of operations in Iraq and Afghanistan over the last several years has steadily increased the number of troops not available for deployment in the Army," he said.
The U.S. defense chief told soldiers at Fort Drum in upstate New York last week that a temporary increase in the force’s size would help expand the period of time soldiers spend at home between deployments, known in military parlance as "dwell time."
Longer dwell time is seen as vital to maintaining the morale of service members.
U.S. Army soldiers currently receive 12 months of dwell time after each 12-month deployment and Army officials want to extend that to two years.
The Army could move to 15 to 18 months of dwell time by mid-2010 when the Pentagon would withdraw an additional five or six combat brigades from Iraq.
(Editing by Eric Beech)