WASHINGTON (AP) — Millions of Americans who are working full-time jobs still rely on federal health care and food assistance programs because of low wages, a bipartisan congressional watchdog says.

A report from the Government Accountability Office found that about 70% of adult workers participating in Medicaid, which provides health care to low-income Americans, and the Supplemental Nutrition Assistance Program, also known as food stamps, are working full time.

The report was requested by Sen. Bernie Sanders, I-Vermont, who said its findings show an urgent need to raise the federal minimum wage.

"At a time when huge corporations like Walmart and McDonald's are making billions in profits and giving their CEOs tens of millions of dollars a year, they're relying on corporate welfare from the federal government by paying their workers starvation wages.," Sanders said in a statement. "This is morally obscene."

He said it was long past time to increase the federal minimum wage from $7.25 an hour to $15.

In the report issued Wednesday, the GAO analyzed data from 15 state agencies covering 11 states, with each agency reporting the employers in their states with the largest numbers of Medicaid and food-stamp beneficiaries.

Among the 15 agencies overseeing the Medicaid and food-stamp programs, Walmart was among the top four employers with beneficiaries in each of the 15 programs. McDonald's was among the top five employers whose workers received federal benefits from 13 of the 15 state agencies.

Other companies that appeared frequently were Dollar Tree and Dollar General.

Sanders said an analysis of the GAO data showed that across nine of the states reviewed — Arkansas, Georgia, Indiana, Maine, Massachusetts, Nebraska, North Carolina, Tennessee and Washington — the largest number of recipients of foods stamps were employed at Walmart and McDonald's.

Asked for comment on the GAO report, Anne Hatfield, a Walmart spokesperson, said, "If not for the employment access Walmart and other companies provide, many more people would be dependent on government assistance."

She said that a small percentage of Walmart's workforce is on public assistance when hired by Walmart. The company strives to "remove employment barriers and create opportunities for individuals that too many overlook," she said.

McDonald's USA said in a statement, "The average starting wage at U.S. corporate-owned restaurants is over $10 per hour and exceeds the federal minimum wage. "