Thousands of U.S. troops returning from Iraq and Afghanistan with physical injuries and mental health problems are encountering an overburdened benefits system, and officials and veterans’ groups worry that the challenge could grow as the nation remains at war.

The disability benefits and health care systems that provide services for about 5 million American veterans have been overloaded for decades, with a current backlog of more than 300,000 claims. And as of Aug. 1, nearly 150,000 National Guard and reservist veterans became eligible for health care and benefits because they were mobilized to fight in Iraq and Afghanistan. That number is rising.

President Bush’s budget for 2005 calls for cutting the Department of Veterans Affairs staff that handles benefits claims, and some veterans report long waits for benefits and confusing claims decisions.

“I love the military; that was my life. But I don’t believe they’re taking care of me now,” said Staff Sgt. Gene Westbrook, 35, of Lawton, Okla. Paralyzed in April in a mortar attack near Baghdad, he has received no disability benefits because his paperwork is missing. He is supporting his wife and three children on his regular military pay of $2,800 a month as he awaits a ruling on whether he will receive $6,500 a month from the VA for his disability.

Through the end of April, the most recent accounting the VA could provide, a total of 166,334 veterans of operations in Iraq and Afghanistan had separated from military service, and 26,633 — 16 percent — had filed benefits claims with the VA for service-connected disabilities. Less than two-thirds of those claims had been processed, leaving more than 9,750 recent veterans waiting.

Officials expect those numbers to increase as the fighting in Iraq and Afghanistan continues.

“I think we’re doing OK now, but I am worried,” VA Secretary Anthony Principi said in a recent interview. “It is something you have to be concerned about. We don’t have a good handle on the extent to which the demand for care and benefits will be a year or five years from now.”