Republican chances of taking the Senate dim

Republican chances of taking control of the Senate were eroded Tuesday as Democrats triumphed in hard-fought races in Connecticut, New York and crucially in West Virginia, exit polls showed.

US media projections showed the Republicans had taken back the House of Representatives in mid-term elections dominated by voter anger over the sour US economy, but they faced a much harder challenge in the Senate.

The Republicans needed to capture 10 seats from Democrats and hold their own to complete a clean sweep of Congress and deliver a stinging rebuke to President Barack Obama after less than two years in office.

Dan Coats in Indiana, John Boozman in Arkansas, and John Hoeven in North Dakota gave the Republicans their first three gains of the night, while Rand Paul and Marco Rubio notched up the burgeoning Tea Party movement's first wins in Kentucky and Florida.

With former White House budget director Rob Portman winning in the swing state of Ohio - crucial to Obama's chances of re-election in 2012 - it was a promising start for the Republicans.

But that was before Joe Manchin. His vital victory over businessman John Raese in West Virginia meant Republicans would have to capture all the remaining seven Democrat seats considered in play to reach the crucial 51 needed.

"I can only say that I want to thank all the people of West Virginia for believing in me. I really truly appreciate every one of them," Manchin said in his victory speech.

Manchin enjoyed sky-high job approval ratings as governor, so Republicans had hoped to tie him closely to Obama's agenda at a time when US voters were angry at the economy and the high unemployment.

He only overcame Raese by declaring his independence from the president and vowing to shoot down climate change legislation.

The first Republican scalp was in Indiana, where Coats saw off former sheriff Brad Ellsworth to take the seat of Democratic heavyweight Evan Bayh who retired in February.

Paul handed an early symbolic victory to the Tea Party, defeating his Democratic rival Jack Conway to be crowned the conservative grassroots movement's first US senator in Kentucky.

"Tonight, there's a Tea Party tidal wave and we're sending a message," Paul told reporters in his victory speech.

Rand, a conservative activist, rocked the political landscape when he defeated establishment candidate Trey Grayson in the May primaries to win the nomination to run in the poor, eastern state.

Republican Rubio, a Hispanic rising star, captured the second Senate seat for the Tea Party after a three-way race in Florida, defeating governor Charlie Crist, running as an independent, and Democratic rival Kendrick Meek.

The Tea Party, which has adopted former Republican vice presidential candidate Sarah Palin as its main mascot, first burst onto the American political scene in 2009 amid growing public anger at the souring economy.

It has no formal leaders or organization, but remains a loose-knit collection of state movements which are committed to smaller government and slashing taxes.

While the movement has successfully tapped into a groundswell of discontent, many US voters remain wary of Tea Party activists, such as Delaware's Christine O'Donnell, whose views are often seen as too extreme.

O'Donnell's loss in Vice President Joe Biden's old seat to Chris Coons gave the Democrats their first win of the night.

Democrat Richard Blumenthal later defeated Linda McMahon, the former CEO of the World Wrestling Entertainment in Connecticut, and party colleague Charles Schumer won in New York, according to exit polls.

The Republicans also held on to South Dakota.

The business end of the night comes later in Nevada, where Tea Party darling Sharron Angle was running a close race against Democratic Senate Majority leader Harry Reid.

Roughly one third of the Senate's 100 seats are up for grabs every two years.