The Republican chairman of the House Budget Committee said his party's budget proposal for 2012 would cut deficits by more than $4 trillion over the next decade, vowing to tackle costly entitlements like Medicare and Medicaid.

The proposal, set to be unveiled Tuesday, would serve as the Republicans' official response to President Obama's proposed $3.7 trillion budget for 2012. The White House claims its plan would cut deficits by $1.1 trillion over a decade.

But Ryan, R-Wis., in an interview with "Fox News Sunday," accused Obama of "punting" and said Republicans' plan would exceed the fiscal goals set by the president's fiscal commission -- which issued a report calling for $4 trillion in cuts. That report never made it out of committee.

"We can't keep kicking this can down the road," Ryan said. "The president has punted. We're not going to follow suit."

The GOP proposal coincides with the ongoing debate over the remainder of the fiscal 2011 budget. Both parties are trying to hammer out a half-year budget before the deadline for a partial government shutdown Friday. From there, they move immediately to the 2012 budget debate.

Ryan said Sunday that the GOP proposal would reform the tax code but focus on spending cuts and entitlement reform to achieve savings.

"We don't have a tax problem," Ryan said. "We have got to stop spending money we don't have."

Though the plan is expected to mostly leave Social Security reform for another day, Ryan proposed big changes to Medicare and Medicaid. For Medicaid, he called for a system of block grants to the states, so the states can "customize" coverage for the poor.

"We want to give governors freedom," he said.

For Medicare, he said the GOP proposal will be modeled after the "premium support" system outlined in an earlier proposal co-authored by him and former White House Budget Director Alice Rivlin. Such a proposal would provide a fixed amount of government assistance toward premiums in the health plan of seniors' choosing. The Ryan-Rivlin plan would call for seniors to pay more for smaller expenses but put a cap on what they could pay out-of-pocket. Ryan, on "Fox News Sunday," did not discuss these details but said the plan would provide less money to wealthy beneficiaries, and stressed that the changes would not affect those 55 and older.

"The biggest driver of our debt is Medicare," Ryan said, adding that the overall goal of the budget changes are to bring down the debt, something he notes Obama's plan does not do.

Ryan said the proposal would also seek a cap on discretionary spending as well as a cap on all spending as a percentage of GDP.

"Our numbers are moving around right now," he said, declining to say what those caps would look like.

Democrats were quick to pounce on Ryan's budget preview, accusing him of sparing oil and gas subsidies at the expense of seniors.

"Paul Ryan made clear that the Republican budget will protect Big Oil companies subsidies over seniors health care," Jesse Ferguson, spokesman for the Democratic Congressional Campaign Committee, said in a statement. "It's already becoming clear who will be the priority in the House Republican budget -- special interests, not middle class families."

Rep. Chris Van Hollen, D-Md., Ryan's Democratic counterpart on the budget committee, said the GOP plan would threaten health care coverage for millions of Americans.

"It is increasingly clear that the House Republicans are more committed to continuing tax breaks to millionaires and big corporate special interests than they are to a serious, balanced approach to reducing deficits," Van Hollen said.

But Ryan said the changes to Medicare and Medicaid would not reduce spending on those programs. Rather, he said, they would slow their rate of growth from an otherwise "unsustainable" trajectory.

He said the proposal could be used against Republicans, but added, "They will have to lie and demagogue to make that a political weapon."