Clinton, a New York senator, and Romney are both under heavy pressure to revive their campaigns after disappointing showings in Iowa. Until recently, Romney led polls in Iowa and New Hampshire, but he finished second in Iowa to former Arkansas Governor Mike Huckabee.

New Hampshire’s primary is the next battleground in the state-by-state process of choosing Republican and Democratic candidates for November’s election to succeed President George W Bush.

A new Reuters/C-SPAN/Zogby poll showed Obama expanding his lead over Clinton to 13 points, 42 per cent to 29 per cent, with former North Carolina Senator John Edwards in third at 17 per cent.

McCain led Romney 36 per cent to 27 per cent in the Republican race, with Huckabee at 10 per cent.

Clinton greeted a handful of supporters at a Manchester polling location before dawn on Tuesday and made similar visits in Nashua, Derry and Concord through the morning.

Asked by a reporter if she needed to win New Hampshire, she made reference to the February 5 “Super Tuesday” round of 22 nominating contests.

“I think the nominating process ends at midnight on February 5,” she said. “I look forward to campaigning across the country.”

Romney predicted the New Hampshire vote would be close and looked ahead. “Republicans are going to get behind me and independents are going to get behind me and we’re going to end up winning this thing,” he said.

The tiny mountain hamlet of Dixville Notch opened the state’s voting shortly after midnight, as it has for every election since 1960, in a balloting display more media circus than civic event.

... contd.