US President Donald Trump and Democratic rival Joe Biden have opened the American presidential election results night with predictable victories and are locked in an edge of the seat battle in all important Florida, where at least 90 per cent of the votes are in.

But, Florida, Georgia and Pennsylvania were still too early to call, and compared with 2016, there were no flips so far on either side. The electoral vote count as of Tuesday night at 10 p.m. EST (8.30 a.m. IST Wednesday morning) placed Biden at 89 and Trump 72.

In a burst of projected results in two hours after the first poll closings, Trump has taken South Dakota, Louisiana, North Dakota, Arkansas, Alabama, Mississippi, Oklahoma, Tennessee, Kentucky, West Virginia, and Indiana.

Biden has bagged Colorado, District of Columbia, New York, Vermont, Connecticut, Delaware, Illinois, Maryland, Massachusetts, New Jersey and Rhode Island. Virginia, once a battleground and now a Democratic stronghold, has also been called for Biden.

Delaware, on the Biden column, has been the former Vice President's hometown since he moved there as a young boy from Scranton, Pennsylvania. Delaware went to former Democratic hopeful Hillary Clinton in 2016. The state last voted for a Republican in 1988.

The projections, a combination of races called by multiple television networks and The Associated Press (AP), are on fairly expected lines so far while US voters remain glued to the crucial Florida numbers. That map has begun lighting up like a slot machine, as anxiety swirls all around.

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.

Biden's victory in Vermont is on expected lines as Democrats have kept the state in their column since 1992. Clinton got a huge win here in 2016. Trump won West Virginia by 42 points in 2016 and Kentucky by nearly 30 points. The last time a Democratic candidate carried West Virginia was Bill Clinton in 1996.

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.