Washington - Republican Bob McDonnell was elected governor of Virginia on Tuesday, recapturing a closely watched US state that voted for Barack Obama in the 2008 presidential election.

The victory came in one of two states where voters on Tuesday chose governors and other statewide offices in an election seen by pundits as an early test of Obama's popularity.

The elections in Virginia and New Jersey have garnered national attention as Republicans hope to regain ground from Obama's centre- left Democrats. They are the first major polls since Obama was elected in November 2008.

Initial results gave McDonnell 61 per cent, compared to 39 per cent for Democratic Party candidate Creigh Deeds, reversing a decade- long string of defeats for Republicans in the Southern state.

In New Jersey, usually a reliably left-leaning state, the race was too close to call between Democratic incumbent Jon Corzine and Republican challenger Chris Christie. An independent candidate, Chris Daggett, was also tapping into voter disaffection and could garner as much as 15 per cent of the vote.

Democrats had hoped to maintain the momentum of last year's election but struggled to harness the excitement that was generated by Obama's candidacy. Republicans see a turning point and a chance to send Obama and his fellow Democrats a signal that their policies of the last year are not supported by all voters.

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 until Tuesday.

McDonnell campaigned on a promise of reviving job growth and smaller government in Virginia, mirroring the national campaign themes of centre-right Republicans. The party is primarily tapping into anger over what some voters perceive as reckless spending by Democrats to revive the economy.

The elections have attracted some major political star power. Obama, Vice President Joe Biden and former president Bill Clinton have 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 were choosing mayors in several large cities, including New York, Atlanta and Pittsburgh, Pennsylvania.

In New York, billionaire Michael Bloomberg looked set to win an unprecedented third four-year term as mayor. Opinion polls ahead of the vote put the 67-year old Bloomberg 12 percentage points ahead of his Democratic challenger William Thompson, 56.

A special election for Congress in upstate New York was also being watched closely. Republican candidate Dede Scozzafava, a moderate with left-leaning views on social issues, quit the race on Saturday after poor showings in opinion surveys and pressure from a conservative third-party candidate. She threw her support behind the Democratic nominee. (dpa)