US President Barack Obama said on Saturday his budget blueprint due to be unveiled next week will aim to reinvigorate America's middle class while introducing reforms to curb the mushrooming deficits.

"Our top priority as a nation, and my top priority as president, must be doing everything we can to reignite the engine of America's growth: a rising, thriving middle class," Obama said in his weekly radio address. "That's our North Star. That must drive every decision we make."

The comments followed reports that in his budget proposal, Obama will make key concessions to Republicans by offering to cut some entitlement programs like the Social Security retirement program and Medicare, a health care plan for the elderly.

According to a senior administration official, the president's fiscal blueprint will slash the deficit by $1.8 trillion over 10 years, in what the official described as a "compromise offer" that cuts federal spending, finds savings in Social Security and raises tax revenue from the wealthy.

While the annual budget deficit is projected at 5.5 percent of gross domestic product for the fiscal year ending in September, under the Obama budget, that would decline to 1.7 percent of GDP by 2023.

Combined with the $2.5 trillion in savings already achieved since negotiations in 2010, the Obama budget would bring total deficit reduction to $4.3 trillion over 10 years, slightly higher than the overall goal agreed to by both parties for stabilizing the national debt.

But the plan has drawn fire from both conservatives and liberals. Republican House Speaker John Boehner warned that Obama had "moved in the wrong direction" by making skimpier entitlement cuts than he had offered in negotiations with Republicans last year.

Liberals immediately were upset by what they saw as Obama caving in to Republicans, with left-wing Senator Bernie Sanders pledging to "do everything in my power to block" Obama's proposal.

But the president defended his ideas, saying his budget will reduce deficits not through spending cuts that will hurt students, seniors and middle-class families, "but through the balanced approach that the American people prefer, and the investments that a growing economy demands."

Obama said his budget blueprint would reduce the deficits by nearly $2 trillion.

According to the president, that will surpass the goal of $4 trillion in deficit reduction that many economists believe will stabilize US finances.

The proposal will also include closing tax loopholes for the wealthy, the president said.

"It's a budget that doesn't spend beyond our means," he argued. "And it's a budget that doesn't make harsh and unnecessary cuts that only serve to slow our economy.... And we'll keep our promise to the next generation by investing in the fundamentals that have always made America strong -- manufacturing and innovation, energy and education."

In a Republican address, Kansas Governor Sam Brownback said that Washington was broke and big spending programs were running out of money.

He called for boosting the entrepreneurial spirit of America to achieve growth.

"Our Republican message is a belief in the power of the people more than the control of government," Brownback said. "This unleashes the creativity of entrepreneurs and the strength of hope and dreams."