WASHINGTON — An aging population and an economy that has been slow to rebound are straining the long-term finances of Social Security and Medicare, the government’s two largest benefit programs.

Those problems are getting new attention Monday as the trustees who oversee the massive programs release their annual financial reports.

Medicare is in worse shape than Social Security because of rising health care costs. But both programs are on a path to become insolvent in the coming decades, unless Congress acts, according to the trustees.

Last year, the trustees projected the Medicare hospital insurance fund for seniors would run out of money in 2024. Social Security’s retirement fund was projected to run dry in 2038, while the disability fund was projected to be drained by 2018.

New projections in March gave a more dire assessment of the disability program, which has seen a spike in applications as more disabled workers lose jobs and apply for benefits.

The nonpartisan Congressional Budget Office said the disability fund would run out of money in 2016. Social Security’s trustees are again urging Congress to shore up the disability system by reallocating money from the retirement program, just as lawmakers did in 1994.

If the Social Security and Medicare funds ever become exhausted, both programs would collect only enough money in payroll taxes to pay partial benefits, the trustees said.

“I don’t know how to make it clear to the public, but in my mind the sirens are going off,” said Mary Johnson, policy analyst for the Senior Citizens League. “I wouldn’t say we’re under attack, but we are in a very, very serious position.”