Congress is working on a bonus for soldiers who were forced to stay in Iraq and Afghanistan past their enlistment.

A House subcommittee has approved a measure that would provide an extra $500 a month in retroactive "special pay" for about 160,000 troops affected by the so-called "stop loss" policy after 9/11. An estimated 12,000 troops currently in that situation would also qualify.

The panel approved the measure as part of a military spending bill that Congress will take up when it returns in September. Congressman John Murtha says the 600-million-dollar cost is justified because some troops were unable to start jobs or attend college when their enlistments were extended. The Pennsylvania Democrat calls that an unfair, "back-door draft."

Military leaders have said the policy is necessary to keep troops with critical skills and maintain the continuity of a unit.