Washington, Jan 6 (DPA) US President Barack Obama is gearing up for a tougher second half of his term in the White House as a new Congress was sworn in Wednesday with Republicans back in control of the House of Representatives.

John Boehner will lead the conservative party's charge after being elected the new speaker of the House. He was ceremoniously handed the speaker's gavel by Nancy Pelosi, who is relegated to minority leader of the Democrats after her left-leaning party suffered an historic defeat in November's congressional elections.

The new Republican majority in the House has vowed to derail as much as it can of Obama's domestic agenda, pledging a vote within a weak to repeal last year's massive overhaul of the health care system, and promising deep cuts in what they consider out-of-control government spending.

"The people voted to end business as usual, and today we begin carrying out their instructions," Boehner said after his election as speaker, to rousing applause from lawmakers of his party.

Yet Republicans will have little chance of getting their most ambitious pieces of legislation through Congress, including the health care repeal, as Democrats still control the upper Senate chamber and Obama wields a veto over all lawmakers' decisions.

The House and Senate were both called to order at noon (1700 GMT), with re-elected and incoming lawmakers being ceremonially sworn into their offices through the afternoon. Vice President Joe Biden was presiding over the proceedings in the Senate.

Democrats and the White House are gearing up for a full-throated defence of their own agenda of the past two years, Tuesday slamming Republicans for starting out their term by trying to undo the health reforms already passed.

But Obama has also called on both sides to avoid an early start to the 2012 presidential elections, urging Republicans to work with him to restore a still fragile economy and lower an unemployment rate that remains near 10 percent.

"Obviously, we've got a lot of work to do," Obama said in an interview Wednesday with The New York Times. "The American people are expecting us to hit the ground running and start working with this new Congress to promote job growth and keep the recovery going."

Boehner also noted the uncertain economic times in his afternoon speech, but focused on Republican priorities of slimming the size of government in order to get the world's largest economy moving again.

"Our spending has caught up with us, and our debt will soon eclipse the size of our entire economy," Boehner said, picking up the key campaign theme that swept Republicans back into power in November's congressional elections.

But Boehner also suggested an awareness of just how fleeting the renewed support for his party could be, amid deep disaffection from the public with the way Congress does business. It was only four years ago that Democrats were swept into control of Congress in the final years of president George W. Bush's term.

"The American people have humbled us," Boehner said, promising to improve transparency of the chamber's workings. "They have reminded us that everything here is on loan from them."

Boehner pledged to work with Democrats and promised a "free exchange of ideas", noting the intense partisanship - "scar tissue" - that has engulfed the chamber in the past years. Among the transparency pledges proposed by Republicans is a new rule that every bill be made available to the public three days before a final vote.

Pelosi also pledged that her party would be willing to work with Republicans on the country's top goal of restoring jobs and the economy.

"We wish them success," Pelosi said. "We must stand ready to find common ground to solve problems and to build a more secure future for all Americans."

Among the first acts of Republicans will be to slim office budgets in Congress by about $35 million, a drop in the bucket of the country's $1.3-trillion deficit in 2010, but hailed by Boehner as a sign that his party is serious about cutting costs.

Republicans will also soon unveil more ambitious plans to cut $100 billion in domestic spending. The Obama administration has warned conservatives against proposing cuts especially to education and innovation.