WASHINGTON — The California National Guard told the state's members of Congress two years ago that the Pentagon was trying to claw back re-enlistment bonuses from thousands of soldiers and even offered a proposal to mitigate the problem, but Congress took no action, according to a senior National Guard official.

The official added that improper bonuses had been paid to National Guard members in every state, raising the possibility that many more soldiers may owe large debts to the Pentagon.

“This is a national issue and affects all states,” Andreas Mueller, the chief of federal policy for the California Guard, wrote in an email to the state's congressional delegation Monday. Attention had focused on California because it was “the only state that audited” bonus payments distributed at the height of the wars in Iraq and Afghanistan, he added.

The Pentagon has been demanding repayment of enlistment bonuses — which often reached $15,000 or more — from thousands of California Guard soldiers, many of whom had served multiple combat tours in Iraq and Afghanistan. Audits completed last month concluded that 9,700 California Guard members were not entitled to the payments or that there had been errors in their paperwork.

Pentagon officials acknowledged Monday that the problem likely extends beyond California.

“We know that the majority (of cases) is out of California. However, there may be other states involved,” said Laura Ochoa, a Pentagon spokeswoman. “We do not have a list of those states at this time.”

“The senior leadership of the department is looking very closely at this matter,” Ochoa said. “We take doing right by our service members very seriously,” she added.

The possibility that more soldiers will have to repay large bonuses paid years ago, when the Pentagon relied heavily on the Guard to supply soldiers for two wars, may increase pressure on Congress to act.

In an interview, Mueller said a provision in a defense bill that has passed the House would have cured at least part of the problem by establishing a 10-year limit on how long the Pentagon could recover bonuses that had been paid improperly.

Final passage of that provision had been uncertain because of the money it would cost. Now, Congress may decide to go further.

On Monday, House Democratic Leader Nancy Pelosi of California sent a letter to Speaker Paul Ryan, R-Wis., and Senate Majority Leader Mitch McConnell, R-Ky., saying that Congress should pass legislation to halt the Pentagon debt recovery “as soon as we gavel back into session” after the Nov. 8 elections.

Both Hillary Clinton and Donald Trump also weighed in on the controversy.

Clinton, in a statement, said that she was “appalled” by the news that the Pentagon was trying to take back the bonuses and that Congress should “swiftly pass legislation to right this wrong.”

Trump, in Florida, called the case another example of wrongdoing in a “corrupt” political system.

“This can only happen with these incompetent people we have,” he said. “No common sense. They're incompetent.”

david.cloud@latimes.com