In a change of Pentagon policy, Defense Secretary Robert Gates announced Wednesday that all active duty Army soldiers deploying to Iraq and Afghanistan will now serve their tours for as long as 15 months, an increase over the standard year-long deployment.

In an acknowledgement of the strains the U.S. military surge in Iraq is having on the military, Gates told reporters that the new policy will be effective immediately on all units in the Central Command area of responsibility. The troops will continue to return home to their stations for not less than 12 months rotations. The rule will apply to all except for of two brigades currently deployed that have already been extended to 16-month deployments.

"Without this action, we would have had to deploy five Army active duty brigades sooner than the 12-month at home goal. I believe it is fairer to all soldiers that all share the burden equally," Gates said, adding that the policy will prevent troops from being informed mid-service that their tour is extended and will provide the Defense Department's capacity to sustain the deployed force.

Gates said the move will also create the capacity for commanders to extend the military surge in Iraq for at least a year, although he said any such decision to do so will depend on conditions on the ground. He did add that he wished the pace of political reconciliation among Iraqis was moving quicker.

Soldiers would be entitled to additional pay of $1,000 a month. The policy change will not affect deployed Marines who will continue with their standard seven-month tours or Army National Guard or Army Reserve, which will continue to serve 12-month tours.

The announcement marked one of the rare occasions when the military has not first told soldiers and their families about extended deployments, before going public with the news. And in a rare flash of temper, Gates acknowledged that a leak within the Pentagon forced his hand.

"I'll be very blunt. Some very thoughtless person in this building made the unilateral decision yesterday to deny the Army the opportunity to notify unit commanders who could then talk to their troops 48 hours before we made a public announcement. And I can't tell you how angry it makes many of us that one individual would create potentially so much hardship, not only for our service men and women, but their families by giving -- by letting them read about something like this in the newspapers," he said.

Currently 145,000 U.S. troops in Iraq, and when the buildup is completed by June, there would be more than 160,000, officials are calculating.

Democrats were quick to criticize the decision.

"Today's announcement just underscores the fact that the burden of the war in Iraq has fallen upon our troops and their families," said House Speaker Nancy Pelosi, D-Calif. "Extending the tours of all active-duty Army personnel is an unacceptable price for our troops and their families to pay."

"What a difference a day makes. Yesterday, extending tours of duty was 'unacceptable' to the President. Today, it is Pentagon policy. American troops and taxpayers are paying the price for a war with no end in sight," said Rep. Rahm Emanuel, D-Ill., chairman of the House Democratic Caucus.

Gates acknowledged that the policy change is a sign of added stress on the Army, as commanders plan for deployments in Iraq into 2010 and troops continuing to operate in Afghanistan.

"I think that what this recognizes, though, is that our forces are stretched. There's no question about that."

FOX News' Jennifer Griffin and Nick Simeone contributed to this report.