ID=2948817President Obama prepared to meet Monday with congressional leaders, as lawmakers said they are close to a deal that could avert a government default later this week.

Obama, visiting a food bank in Washington, D.C., told reporters that if congressional Republicans don't agree to an increase in the debt ceiling by Thursday, "we stand a good chance of defaulting."

Obama will meet this afternoon with bipartisan congressional leaders: Senate Majority Leader Harry Reid, D-Nevada; Senate Minority Leader Mitch McConnell, R-Ky.; House Speaker John Boehner, R-Ohio; and House Minority Leader Nancy Pelosi, D-Cal. Vice President Biden will also attend the session.

Negotiators have made "progress" on a deal to raise the $16.7 trillion debt ceiling and re-open the government after a 14-day partial shutdown, Obama told reporters -- but nothing is final "until the details are done."

Said the president: "We'll see this afternoon whether this progress is real."

McConnell spokesman Don Stewart said "We're engaged in good faith negotiations and those talks will continue."

Reid and McConnell, the Senate's top Republican, began talks over the weekend in search of an agreement that would lift the $16.7 trillion budget ceiling before the government hits it on Thursday. The deal could also end the partial government shutdown, now in its 14th day.

On Capitol Hill, Reid told reporters that "we're getting close" to an agreement.

Reid met privately Monday morning with McConnell, ahead of the White House meeting. Reid has been optimistic that he and McConnell can reach an agreement to end the shutdown and avoid default.

An agreement by the Democratic-run Senate must also be approved by the Republican-run House.

House Republicans ceded negotiations to Senate leaders after Obama rejected Boehner's most recent offer to raise the debt ceiling for six weeks.

A key issue in the current talks is whether the agreement will affect unpopular, across-the-board cuts known as the sequester. Democrats would like to turn off the cuts for at least two years in exchange for other spending reforms, but Republicans want to maintain the stricter spending limits.

House Republican leaders are scheduled to meet Monday; a full GOP conference meeting is set for Tuesday.

At one time, congressional Republicans said they would not vote for a new spending plan or raise the debt ceiling unless Obama delayed parts of the new health care law -- but such delays are not part of the proposed agreement.

Obama warmed up for the congressional meeting by visiting Martha's Table, which serves low income families in Washington, D.C.

Wearing a green apron, Obama spoke with furloughed federal workers who have volunteered at the food bank, praising them for "giving back to the community."

As for the shutdown and debt ceiling disputes, Obama denounced what he called Republican "brinksmanship," and put the onus on the GOP to reach agreement.

"There are going to be differences between the parties," Obama said. "There are going to be differences in terms of budget priorities. But we don't need to inflict pain on the American people, or risk the possibility of America's full faith and credit being damaged just because one side is not getting its way."

He added: "This whole shutdown has been completely unnecessary."

Contributing: The Associated Press