President Obama on Monday said the federal government faces a "good chance of defaulting" if Republicans can't unite behind a plan to raise the nation's borrowing limit.

Obama made the remarks during a surprise visit to a D.C. food bank Monday, leaving the White House to meet with furloughed federal workers who have been doing volunteer work during the government shutdown.

“This week if we don't start making some real progress, both the House and the Senate and if Republicans aren't willing to set aside their partisan concerns in order to do what's right for the country, we stand a good chance of defaulting,” the president told reporters.

Obama said defaulting could have a “devastating effect on our economy.”

The president added, however, that leaders in the Senate were making progress on a potential deal.

He said there has been “some progress on the Senate side with Republicans recognizing it’s not tenable, it’s not smart, it’s not good for the American people to let America default.”

Senate Majority Leader Harry Reid, D-Nev., and Senate Minority Leader Mitch McConnell, R-Ky., are spearheading negotiations in the upper chamber. The two leaders are trading proposals about a short-term increase in the debt limit and a bill that would fund the government for roughly six months.

Obama is also set to host Democratic and Republican congressional leaders at the White House at 3 p.m. on Monday afternoon.

“This afternoon I am going to once again urge them to open the government and urge them to make sure that the United States government is paying its bills,” he said.

During the government shutdown —now in its 14th day — Obama has made quick stops outside the White House to highlight the impact of the unending fiscal feuds.

Last week, Obama traveled to a restaurant just blocks from the White House, which was offering lunch specials to furloughed federal workers.

Obama praised those volunteering at Martha’s Table, a non-profit food bank, on Monday.

He said they were showing "the kind of spirit that we have among all kinds of federal workers all across the country.”

“Because of the politics, they’re not able to do their jobs,” he added.

Assistant Managing Editor Meghashyam Mali contributed to this report.

This story was published at 12:09 p.m. and has been updated.