Biden 230, Trump 213: Red and blue states not budging, US lurches towards nail biting finish

New York :  With the results in the US presidential polls suggesting a close contest in the key battleground states of Pennsylvania,  Michigan,  Iowa and Wisconsin, Donald Trump is so far projected to hold 21 states, including Texas and must-win Florida, having outperformed pollsters' predictions.

President Donald Trump and Democratic rival Joe Biden opened their tally with a predictable string of victories while key prizes including Florida, Georgia, North Carolina, Wisconsin, Michigan and Pennsylvania remain too early to call.

Trump's challenger Joe Biden could clinch Arizona, while projections have him securing a host of reliably Democratic states.  Brimming confidence,  as much as suspense, Biden has told supporters in Delaware that the election is "not over until every ballot is counted" and insists: "We are on track to win".

For his part, Trump tweeted declaring "a big win" and promises a statement but has a post hidden by Twitter after accusing opponents of trying to "steal" the election.

By all accounts,  the US has seen the highest turnout in more than a century and counting is likely to take longer than usual.

Trump has picked up South Dakota, Missouri, Louisiana, Nebraska, North Dakota, Arkansas, Alabama, Mississippi, Oklahoma, Tennessee, Kentucky, West Virginia, Wyoming and Indiana, while Biden has won California, Colorado, New Hampshire, District of Columbia, New York, Vermont, Connecticut, Delaware, Illinois, Maryland, Massachusetts, New Jersey and Rhode Island.

Wild swings were expected in the early hours because of the split between mail in voting and final day numbers.  Early votes are projected to generally favour Biden, final day numbers are likely to be strong for Republicans.

While Trump is tracking results from the White House, where a new fence has been erected to throw an extra ring of security, Biden and his running mate Kamala Harris have chosen Delaware as their election night hub.

On Tuesday, Americans flocked to the polls in record numbers in the middle of the raging Covid-19 pandemic which has killed 232,529 people in the country and infected 9,376,293 others, as well as upended the lives and work for millions.

Even before Election Day, a record number of Americans had cast mail in votes, accounting for more than 70 per cent of the total vote in 2016.

Based on projections ahead of the counting, Trump came into election night with a narrow path to victory, Biden with several potential paths, hinging on wins in Wisconsin, Michigan and Pennsylvania.

In parallel, the legal battle that Trump has been pointing to has begun, with Republican lawyers on Election Day challenging mail-in ballots in a crucial Democratic-leaning district near Philadelphia.

(With input from CNN and agencies)