The White House announced that a planned meeting between President Obama and congressional leaders Monday afternoon had been postponed to allow fiscal negotiations to continue on Capitol Hill.

“The president's 3:00 pm meeting with the bipartisan leadership has been postponed to allow leaders in the Senate time to continue making important progress towards a solution that raises the debt limit and reopens the government,” the White House said in a statement.

Obama was expected to meet with Speaker John Boehner, R-Ohio, House Minority Leader Nancy Pelosi, D-Calif., Senate Majority Leader Harry Reid, D-Nev., and Senate Minority Leader Mitch McConnell, R-Ky., on Monday afternoon.

Senate leaders voiced new optimism on Monday about the prospects of ending a government shutdown now in its 14th day and lifting the debt ceiling before the federal government reaches its borrowing limit around Oct. 17.

"Constructive, good faith negotiations continue between the Republican leader and me," Reid said on the Senate floor. "I'm very optimistic that we will reach an agreement that's reasonable in nature this week to reopen the government, pay the nation's bills and begin long term negotiations to put our country on sound fiscal footing."

“We have had an opportunity over the last couple of days to have some very constructive exchanges of views about how to move forward,” McConnell added from the Senate floor. “Those discussions continue, and I share [the] optimism that we’re going to get a result that will be acceptable to both sides.”

The president also sounded optimistic about a possible breakthrough on Monday but urged caution until a deal is finalized.

"If we don't start making some real progress both in the House and the Senate, and if Republicans aren't willing to set aside some of their partisan concerns in order to do what's right for the country, we stand a good chance of defaulting," Obama said during a visit to a D.C. food pantry.

Republicans and Democrats are trying to hash out a deal not just on keeping the government funded and raising the debt ceiling, but also across-the-board budget cuts that went into effect this year. Democrats want to undo the so-called sequester cuts while Republicans want to lock them in for as long as possible.