WASHINGTON - About 20,000 veterans forced out of the military early by a combat-related injury could be eligible for hundreds in special compensation pay under new rules outlined by the services this month.

The change, mandated by Congress last year, makes veterans who served less than 20 years eligible for Combat-Related Special Compensation payments from the Defense Department.

Those funds are designed to restore money deducted from troops' military retirement accounts because they also receive veterans' disability payouts. The offset can trim a significant portion of the military retirement pay, and veterans groups have lobbied for years to end the deductions.

Army spokesman Lt. Col. Mike Moose said that since 2002, servicemembers with 20 years of military service and a combat-related injury have been receiving monthly Combat-Related Special Compensation, but those with fewer years were not eligible.

Now, the new change is effective back to Jan. 1 of this year, making all combat veterans eligible to apply for six months of retroactive payments and future monthly compensation, he said.

To receive the special compensation, veterans must be currently receiving military retired pay and veterans disability payments, and must have a 10 percent or greater rated disability recognized by the military as combat related.

The amount of the monthly CRSC pay will be based on troops' rank, years of service and severity of their injury, Moose said.

In some cases the formula for Combat-Related Special Compensation could actually reduce a veteran's total monthly payments, but Moose said defense finance officials will calculate all of the disability pay impact to make sure veterans are receiving the highest payouts possible.

All veterans, including recently separated servicemembers, will have to apply to receive the new compensation, Moose said.

Claim forms and contacts for each of the services are available through the Army's CRSC site.

Congressional researchers estimated the new program will cost the Defense Department about $680 million over the next 10 years.