First and foremost, he said, retirement and disability benefits for millions of Americans would be at risk.

“In a government shutdown, Social Security checks still go out on time,” Obama said. “In an economic shutdown, if we don’t raise the debt ceiling, they don’t go out on time.”

More than 57 million Americans receive monthly benefits from the Social Security Administration. The average monthly check for retirees totaled $1,224 in September.

The president’s remarks followed a Treasury Department report detailing catastrophic consequences for Congress failing to allow the government to continue borrowing money to cover expenses. Not raising the so-called “debt ceiling” by Oct. 17 could trigger “a financial crisis and recession that could echo the events of 2008 or worse,” the report said.

A lapse in Social Security would be bad news for the 21 million seniors the benefits have lifted from poverty, and it would certainly disrupt the broader economy. A report by the AARP Public Policy Institute this week estimated Social Security benefits accounted for $1.2 trillion worth of economic output last year.

Republicans in Congress have said they plan to use the debt ceiling as leverage to force Democrats to agree to spending cuts, but Obama has said he’ll refuse to negotiate. His comment Thursday is part of an effort to increase pressure on Republicans to get them to give up their demands.

The last time the debt ceiling deadline approached, in 2011, Obama said, “I cannot guarantee that those checks go out” if Congress didn’t raise the debt limit, which it ultimately did.