U.S. President Barack Obama is meeting with top congressional leaders at the White House to seek out what has so far been an elusive deal with Republicans on raising the nation's debt ceiling.

They face an August 2nd deadline before the current ceiling is reached and United States defaults on its debt for the first time in its history.

U.S. Treasury Secretary Timothy Geithner told NBC television's Meet the Press Sunday that Mr. Obama wants “the biggest deal possible” on debt reduction. He said failing to raise the amount the government can borrow to pay what it owes investors would cause “catastrophic damage” to the U.S. economy.

The new head of the International Monetary Fund, Christine Lagarde, said on ABC's This Week that there would be “real nasty consequences” for the global economy, too — including interest rate increases and tumbling stock markets.

But Lagarde says she cannot imagine U.S. leaders letting the nation default on its debts.

The Speaker of the U.S. House of Representatives, Republican John Boehner, said Saturday he is giving up efforts to reach a comprehensive deal with the White House to cut the federal deficit by $4 trillion over the next 10 years.

Boehner said he told President Obama that he wants to pursue a smaller $2 trillion deficit reduction deal.

Republicans have been adamant that they will not support higher taxes. Instead, Boehner said negotiators should focus on deficit reductions identified by a bipartisan group led by Vice President Joe Biden.

Mr. Obama said earlier that congressional Democrats and Republicans need to make political sacrifices to meet the nation's fiscal challenges.