WASHINGTON - Top US Republican lawmakers Tuesday urged President Barack Obama to specify details on government spending cuts to break the current stalemate over "fiscal cliff" negotiations.

"Any solution to our spending and debt problem has to involve cuts to out-of-control Washington spending," Senate Republican Leader Mitch McConnell said Tuesday.

"I know that might sound obvious, but for all the President's talk about the need for a balanced approach, the truth is, he and his Democrat allies simply refuse to be pinned down on spending cuts," said McConnell, the top GOP lawmaker of the upper chamber of US Congress.

Unless US Congress acts by the end of this year, a combination of tax increases and sweeping spending cuts, dubbed the "fiscal cliff," with a combined amount of about 600 billion US dollars, is set to kick in.

Republicans and Democrats haven't broken the logjam, as Republicans pressed for big entitlement spending cuts while Democrats urged for higher tax rates for the wealthy.

"When it came to offering his idea of a balanced approach, the President was vague about cuts but very specific in his request for more government spending," said McConnell.

House Speaker John Boehner, the top GOP lawmaker of the lower chamber of US Congress, also urged Tuesday Obama to "get serious " about the "fiscal cliff" negotiation and offer specific spending cuts proposals.

A group of corporate executives from the Business Roundtable, a leading US business association, Tuesday urged Democrats and Republicans to ink a debt reduction deal, saying both revenue increase and entitlement program cuts should be part of the deal.