U.S. Treasury Secretary Timothy Geithner says President Barack Obama wants “the biggest deal possible” on debt reduction.

Geithner spoke Sunday as the president prepared for a White House meeting with congressional leaders. President Obama has been working with top lawmakers on what has been an elusive deal with Republicans to raise the nation’s debt ceiling by an August 2nd deadline.

Geithner told NBC television’s Meet the Press that failing to reach a deal on raising 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 if the White House and Congress cannot agree, 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.