WASHINGTON (AP) — Congressional investigators have designated veterans' health care as a "high risk" budget issue that threatens big costs to taxpayers unless longstanding problems are addressed.

The nonpartisan Government Accountability Office says health care costs at the Department of Veterans Affairs have more than doubled since 2002, to more than $55 billion a year, as a result of the Iraq and Afghanistan wars and the aging of Vietnam-era veterans.

The GAO praised a new law overhauling the VA in the wake of a scandal over long wait times for veterans seeking care. But it said officials must ensure that veterans obtain needed care, whether from the VA or from outside providers authorized under the new law.

The VA said it shares GAO's goal and is working of ensuring veterans receive high-quality health care.