Obama faces a fight over the budget with Republicans, who say his spending cuts are not deep enough [GETTY]

Barack Obama has said he is determined to curb the US budget deficit, a day after he unveiled an ambitious austerity plan.

Speaking in Washington DC on Tuesday, the US president said: "When I took office I pledged to cut the deficit by half by the end of my first term. Our budget needs that. The budget requires to make some tough choices."

He said medicare and medical aid were the "single-biggest contributor to the deficit", and cautioned that the steps he was taking "are going to be difficult and that's why they require Democrats, Republicans and independents to work together".

"We'll not be adding more to the national debt," Obama said.

"We'll not be running up the credit card any more. We're going to make some key investments in areas like education. Medicare and medical aid are huge problems and that's why we have started with that in a serious way."

Obama released on Monday a $3.73tn budget for 2012 that calls for spending cuts and investment in areas such as education and energy efficiency.

He faces a fight over the budget with congressional Republicans, who say his spending cuts are not deep enough to attack the US deficit, which will hit an all-time high of $1.65tn this year.

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Investment strategist Ashraf Laidi talks to Al Jazeera about the upcoming bitter US budget battle

But it is expected to drop sharply to $1.1tn in 2012, with an expected improvement in the economy and as reductions in Social Security withholding and business taxes expire.

Obama's 2012 budget would actually add $8bn to the projected deficit for that year because the bulk of the savings he will achieve through a freeze in many domestic programmes would be devoted to increased spending in areas the president considers priorities, such as education, clean energy and high-speed rail.

"We have more work to do to live up to our promise by repairing the damage this brutal recession has inflicted on our people," he said on Monday.

Republicans, who took control of the House in the November elections and picked up seats in the senate in part because of voter anger over the soaring deficit, called Obama's efforts too timid. 

The legislators are set to begin debating on Tuesday $61bn in cuts for the remaining seven months of fiscal 2011.

"Presidents are elected to lead and address big challenges," Paul Ryan, the chairman of the Republican House budget committee of Wisconsin, said.

"The big challenge facing our economy today and our country tomorrow is the debt crisis. He's making it worse, not better."

Source: Al Jazeera and agencies