WASHINGTON - US President Barack Obama on Sunday criticized his rival Republicans for failing to sign a large bargain deal and resolve the so-called "fiscal cliff."

"The offers that I've made to them have been so fair that a lot of Democrats get mad at me," Obama said in an interview on NBC, following the failure of his talks with US House Speaker John Boehner before Christmas due to some GOP lawmakers' intransigence on anti-tax hikes.

Obama said he had offered to make some significant changes to US entitlement programs to reduce the government deficit.

Unless Congress acts by the end of the year, a combination of tax increases and sweeping spending cuts totaling about 600 billion US dollars will kick in, the effects of which could thrust the economy back into recession.

The president said he was "modestly optimistic" about a possible plan and the pressure now was on Congress to produce such a plan to solve the looming tax increase and government spending cuts.

Republican lawmakers' top priority seemed to be maintaining the low tax rates for the wealthy rather than a deficit reduction, Obama said, adding that a failure to strike a bipartisan deal in the next 48 hours would "hurt our economy badly."