The Army will prevent soldiers in units set to deploy to Iraq (search) and Afghanistan (search) from leaving the service at the end of their terms, a top general said Wednesday.

The announcement, an expansion of an Army program called "stop-loss," (search) means that thousands of soldiers who had expected to retire or otherwise leave the military will have to stay on for the duration of their deployment to those combat zones.

The expansion affects units that are 90 days away or less from deploying, said Lt. Gen. Frank L. "Buster" Hagenbeck, the Army's deputy chief of staff for personnel. Commanders have the ability to make exceptions for soldiers with special circumstances; otherwise, soldiers won't be able to leave the service or transfer from their unit until they return to their home base after the deployment.

The move will allow the Army to keep units together as they deploy, Hagenbeck said. Units with new recruits or recently transferred soldiers would not perform as well because the troops would not have had time to work together.

"The rationale is to have cohesive, trained units going to war together," Hagenbeck said.

Previously, the Army had prevented soldiers from leaving certain units scheduled for deployment to Afghanistan or Iraq. But Wednesday's move is the first time since Sept. 11, 2001, that the stop-loss program has been ordered so widely.

The announcement comes as the Army is struggling to find fresh units to continue the occupation of Iraq. Almost every Army combat unit has faced or will face deployment there or in Afghanistan, and increased violence has forced the deployment of an additional 20,000 troops to the region, straining units even further.

Some criticize the stop-loss program as contrary to the concept of an all-volunteer military force. Soldiers planning to retire and get on with their lives now face months away from their families and homes.

In an opinion piece in Wednesday's New York Times, Andrew Exum, a former Army captain who served under Hagenbeck in the 10th Mountain Division in Afghanistan, called the treatment of soldiers under stop-loss programs "shameful."

"Many, if not most, of the soldiers in this latest Iraq-bound wave are already veterans of several tours in Iraq and Afghanistan," he wrote. "They have honorably completed their active duty obligations. But like draftees, they have been conscripted to meet the additional needs in Iraq."

Hagenbeck said the stop-loss move is necessary only because the Army is also undergoing a major reorganization that requires some units to be taken off-line while they are restructured.

Hagenbeck had no numbers on how many soldiers would be affected.

Without the program, an average division would have to replace 4,000 soldiers — perhaps one-quarter to one-fifth of its strength — before or during a deployment, according an Army press release.