Gates to Expand U.S. Army by Adding 22,000 New Troops

Defense Secretary Robert Gates announced plans Monday to temporarily expand the U.S. Army by adding 22,000 new troops.

Gates said he will increase the number of active duty soldiers from 547,000 to 569,000 to ensure deploying units are "properly manned."

This is the second time since 2007 that the military has determined it doesn't have a large enough force. Gates had already increased the size of the Army and Marine Corps shortly after taking the Pentagon job.

The Defense Secretary, who spoke to reporters during a joint press conference Monday alongside top U.S. commander Admiral Mike Mullen, cited escalating violence in Afghanistan and Pakistan as reason for the decision.

"I came into this job with the belief that we didn't have enough forces to support combat operations in Iraq and Afghanistan," Gates said, though he noted the U.S. military's recent withdrawal from major cities in Iraq.

Also causing a shortage is the decision earlier this year to stop the unpopular practice of keeping troops beyond their enlistment dates, a practice known as "stop-loss."

"The cumulative effect of these factors is that the army faces a period where its ability to continue to deploy combat units (with enough troops) is at risk," Gates said.

"This is a temporary challenge that will peak in the coming year and abate over the course of the next three years," he added.

He also said he would not seek additional money for the extra troops in the 2009 and 2010 fiscal year budgets.

"This decision will result in additional tough choices for the department," Gates. "However, I'm convinced that this is an important and necessary step to ensure that we continue to properly support the needs of our commanders in the field while providing relief for our current force and their families."

Sen. Joe Lieberman, ID-CT -- a strong proponent of the measure -- praised Gates' decision Monday, saying, "I commend Secretary Gates for making this decision, which will provide much needed relief to our brave soldiers and their families."

"I have already introduced an amendment to give Secretary Gates the new authority he will need to add up to 30,000 additional soldiers, and I call upon my colleagues to vote to support our troops this week," he said.

Lieberman had proposed an amendment to the National Defense Authorization Act that gives extended authorizations to Gates to increase Army end strength from 2010 to 2012.

FOX News' Jennifer Griffin and the Associated Press contributed to this report.