Top Republican lawmakers will send a letter to Secretary of Defense Ash Carter on Tuesday asking him to find a way to ensure that thousands of California National Guard members aren't forced to give back re-enlistment bonuses.

The Washington Examiner received a copy of the letter by House Majority Leader Kevin McCarthy of California, House Veterans' Affairs Chairman Jeff Miller, House Foreign Affairs Chairman Ed Royce, House Armed Services Chairman Mac Thornberry and more than 20 other lawmakers. The lawmakers will ask the Pentagon to halt all attempts to reclaim $20 million in bonuses that were improperly given by recruiters in the Golden State.

"We are dismayed that our men and women who answered their country's call to duty are now being forced to repay what was promised to them in exchange for their honorable service," the letter states. "Some have faced the threat of wage garnishments and tax liens if they refuse. This is no way to treat those who have fulfilled their commitments to our country. They should be held harmless in light of the fraud that was perpetrated upon them by overzealous recruiters."

In 2011, Army Master Sgt. Tony Jaffe was convicted of criminal misconduct for handing out millions of dollars to officers and enlisted personnel who did not qualify in an attempt to increase recruitment and retention figures. At the time they were paid, the service members had no idea the bonuses were improper.

The Pentagon on Monday urged the 10,000 affected troops to apply for a waiver to have the debts forgiven.

But House leaders said the situation, including how it is resolved, is of "grave concern" to legislators, prompting the letter and possible congressional hearings.