Washington - Republicans emerged victorious Tuesday in two US state elections that were viewed as an early measure of President Barack Obama's popularity.

Bob McDonnell was elected governor of Virginia in a landslide, winning 59 per cent to 41 per cent for Democrat Creigh Deeds and recapturing a state that voted for Obama exactly one year ago.

In New Jersey, usually a reliably left-leaning state, Republican Chris Christie defeated the Democratic incumbent Governor Jon Corzine by 49-45 per cent.

The elections in Virginia and New Jersey were the first major polls since Obama was elected. But the November 2010 congressional elections will be the bigger test, when the entire House of Representatives and one-third of the Senate is up for grabs.

The country's struggling economy was a dominant issue in both states. Republicans tapped into anger over still-rising unemployment and what some voters perceive as reckless spending by centre-left Democrats to revive the economy.

Both elections garnered national attention as Republicans looked to reverse their fortunes of the last few years. Democrats hoped to maintain the momentum of the election a year ago but struggled to harness the excitement that was generated by Obama's candidacy.

Michael Steele, chairman of the Republican National Committee, called the victory a "blow" to Obama's Democrats and "a clear signal that voters have had enough of the president's liberal agenda."

White House spokesman Robert Gibbs had played down the day's elections, warning against drawing too many inferences for the Democrats' electoral future.

"We don't look at either of these gubernatorial races ... as something that portends a lot for our legislative efforts going forward or political prospects in 2010," Gibbs said.

A majority of Virginia voted for Obama a year ago, marking the first time the state sided with a Democrat for president in more than four decades. Republicans had also lost the state's last two elections for governor before Tuesday.

McDonnell campaigned on a promise of reviving job growth and smaller government in Virginia, mirroring the national campaign themes of centre-right Republicans.

Christie, a former prosecutor, campaigned heavily on curbing corruption in New Jersey, a state that has been dogged by political scandals.

The elections attracted some major political star power. Obama, Vice President Joe Biden and former president Bill Clinton all returned to the campaign trail over the last month. Top Republicans including former presidential candidates John McCain, Mitt Romney and Mike Huckabee also campaigned.

Voters also choose mayors Tuesday in several major cities, including New York, Atlanta and Pittsburgh, Pennsylvania.

In New York, billionaire Michael Bloomberg captured a third four-year term after convincing the City Council to extend mayoral term limits. The city had imposed a two-term limit in the 1990s.

Democrats can take heart from a major upset in a special election for Congress in upstate New York. Bill Owens captured a district along the Canadian border that has been a Republican stronghold for more than a century.

Owens benefited from a split among conservatives. Republican Party candidate Dede Scozzafava, a moderate with left-leaning views on social issues, quit the race on Saturday after many of her party's national figures threw their support behind a conservative third-party candidate, Doug Hoffman. (dpa)