01.20: Barack Obama has opened up a clear lead in the electoral college with 98 votes to 39 for Republican rival John McCain, according to network projections.

01.13: Some networks are already projecting Obama as winner in Pennsylvania, a state which Mr McCain said he had to win if the Republicans were to hold on to the White House. He was also projected to win in New Hampshire, which had been a Republican target state.

Results elsewhere yielded no surprises as Mr McCain picked up a slew of deep red southern states and much of the eastern seaboard fell to Mr Obama. The Republican candidate took projected wins in Oklahoma, Tennessee, South Carolina and West Virginia while Mr Obama was the victor in Maryland, New Jersey, Maine, Connecticut, Delaware, the District of Columbia, Massachussetts and his home state of Illinois.

12.30 GMT: John McCain and Barack Obama have both taken their first win of the night with the networks calling Kentucky for the Republican and Vermont for his Democratic rival.

In the traditional red state of Kentucky, with 11 per cent of precincts reporting, Mr McCain was pulling away from his opponent, with a 52 to 47 per cent lead. Its eight electoral votes now look set to go to the Arizona senator, while Mr Obama will take three from his projected win in the blue state of Vermont.

The results will come as no surprise to the two candidates, who have been banking on their respective states since early on in the campaign season. Both will be looking to Virginia, a key battleground in this year's election, for an early indication of which way tonight will go.

Polls are soon to close in Florida and Ohio, also crucial swing states, shortly followed by the blue-collar states of Pennsylvania and Michigan. Precincts have already begun reporting in Indiana, usually a deep red state that is up for grabs this year, and the two candidates are currently in a dead heat.

A clear majority of American first-time voters are casting their ballots for Barack Obama, according to exit data released just as the first polls closed in Indiana and Kentucky.

Some 72 per cent of newly registered voters are backing the Democrat candidate, early exit polls show, underscoring the Obama camp’s success in energising to the young and politically inactive.

Unsurprisingly, the economy was emerging as the most important issue for a clear majority of American voters, with 62 per cent citing it as the key factor in their decision.

10 per cent said Iraq was the top electoral issue, closely followed by nine per cent who cited terrorism. The issues seemed to be acting as a dividing line between Obama and McCain supporters, with 63 per cent of voters who said Iraq was most important opting for the Democrat and a massive 83 per cent of those most concerned by terrorism choosing his Republican rival.

Today, turnout looked set to break records as millions of voters flooded polling stations all over the country, many attended by long queues snaking through rainy parking lots. Some voters waited several hours to cast their votes in an election that will make history whatever the outcome, with either an African American or a woman entering the White House for the first time.

More than 100 million people were expected to trek to the polls, while 30 million advance ballots were cast in the state-by-state electoral battle, with many predicting turnout could be the highest for a hundred years

Mr Obama had a solid lead in final national polls and held the edge in a string of battleground states that could still swing the election either way, as both candidates hunted the 270 electoral college votes needed to win.

Voters braved long waits in the rain or shivering cold at the climax of the longest and costliest White House race in history.

Mr Obama made a short election day trip to the midwestern swing state of Indiana, after casting his vote alongside wife Michelle with daughters Sasha and Malia close by.

“I feel great and it was fun, I had a chance to vote with my daughters,” he said.

“I noticed that Michelle took a long time though. I had to check to see who she was voting for,” the Hawaiian-born US senator from Illinois, 47, joked.

However Mr Obama’s moment was tinged with personal tragedy following the death of the grandmother who raised him on the eve of election day. Madelyn Dunham, known to Mr Obama as Toots, died in Hawaii yesterday following a long battle with cancer.

Mr McCain kept silent as he voted in his home state of Arizona, but later returned to the campaign trail in a feverish last-ditch effort to win over undecideds and pull out a surprise victory.

The defiant Republican candidate led a boisterous rally in Grand Junction, Colorado, promising supporters:“We’re going to win it."

His running mate, Alaska Governor Sarah Palin, cast her ballot in her hometown of Wasilla and said she was “optimistic and confident” of becoming the first woman US vice president.

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