WASHINGTON - Republicans eagerly geared up for a battle in Congress this week, warning Democrats of an aggressive push to slash spending and an early assault on President Barack Obama's signature health care reform.

With most politicians already eyeing the 2012 presidential election, the United States Congress returns on Wednesday with Republicans in control of the House of Representatives and a slimmed-down Democratic majority in the Senate.

Buoyed by their gains in the November mid-term elections that also saw the grassroots conservative Tea Party movement win its first lawmakers, Republicans are chomping at the bit to try to unravel two years of legislation enacted by Obama's Democrats.

Topping the Republicans' "to do" list are the nation's $1.3-trillion budget deficit and health care reform, with rightwing lawmakers saying they are responding to voters' anger at the stagnant economy and high unemployment.

Representative Fred Upton, who takes over as chair of the powerful Energy and Commerce Committee, vowed tough oversight and "to bring up spending reductions virtually every week."

And he told Fox News on Sunday his committee would hold a vote on moving to repeal Obama's health care reform before the presidential State of the Union address at the end of January.

Republicans cannot repeal health reform while Obama has a presidential veto, but plan instead to block White House efforts to fund its implementation.

"If we pass this bill, it will put enormous pressure on the Senate to do the same thing. But then we're going to go after this bill piece by piece," Upton said.

Obama's signature legislation, pushed through Congress despite huge Republican opposition early last year, aims to ensure that all Americans have health care insurance.

But Tea Party favorite Michele Bachmann told CBS: "Obamacare will bankrupt the country ... It's very costly, it's unwieldy.

"So we will put forth a clean repeal bill of Obamacare."

In his weekly national address on Saturday, Obama reminded Republicans taking control of the House of Representatives that they have a "shared responsibility to move this country forward."

But serving notice that a spirit of bi-partisanship hesitantly forged in late December looked set to evaporate, Representative Darrell Issa said: "I think we're going to be in a constant battle over jobs and the economy."

Issa, who will be the new chairman of the House Oversight and Government Reform Committee and who last year called the Obama administration "one of the most corrupt," also warned he intends to rigorously oversee spending.

The Republican bid to rein in spending appears focused in part on the nation's debt ceiling.

Agence France-Presse