Hillary Clinton and Donald Trump were locked in a dead heat on Tuesday in their historic clash for White House, as the world waited anxiously for results from the key battleground states that will decide the winner.

A deeply divided electorate of about 200 million Americans were asked to make a momentous choice between electing the nation's first woman president, or handing the reins of power to a billionaire populist who has upended US politics with his improbable outsider campaign.

With voting over in most eastern states and Americans still lining up to cast their ballots on the West Coast, television networks called 16 states so far for the Republican Trump -- a band of red on the electoral map stretching from South Carolina to Texas.

Clinton was credited with nine states—Connecticut, Delaware, Illinois, Maryland, Massachusetts, New Jersey, New York, Rhode Island and Vermont—as well as the capital, Washington DC, giving her a notional lead in terms of electoral college votes.

But all eyes were on the tight race in Florida, a must-win race for Trump, who would find it hard to cobble together a majority without the Sunshine State's 29 electoral college votes.

If Florida goes to Clinton, the next big challenges will be Pennsylvania, Ohio and Virginia -- states that will likely decide the result of the long, bruising contest for the right to lead the world's biggest economy.

On the legislative side, the Republicans were on course to retain their majority in the US House of Representatives, according to network projections -- a situation that has been a thorn in the side of incumbent US President Barack Obama.

As of roughly 0530 GMT on Wednesday, Republican Donald Trump had earned 245 of the 270 electoral college votes he needs to secure the US presidency, according to network projections.

His Democratic rival Hillary Clinton had earned 215 electoral votes.

Candidates are racing to hit the magic number of 270 electoral votes, which reprsents an absolute majority of the 538 members of the electoral college, with the number from each state based on its population size.

Eight states were still too close to call including Michigan, Pennsylvania and Wisconsin—all vital to Clinton’s fading chances of victory.

The others are Alaska, Arizona, Maine, Minnesota and New Hampshire.

Trump (245)

Alabama (9)

Arkansas (6)

Florida (29)

Georgia (16)

Idaho (4)

Iowa (6)

Indiana (11)

Kansas (6)

Kentucky (8)

Louisiana (8)

Mississippi (6)

Missouri (10)

Montana  (3)

Nebraska (5)

North Carolina (15)

North Dakota (3)

Ohio (18)

Oklahoma (7)

South Carolina (9)

South Dakota (3)

Tennessee (11)

Texas (38)

Utah (6)

West Virginia (5)

Wyoming (3)

Clinton (215)

California (55)

Colorado (9)

Connecticut (7)

Delaware (3)

Hawaii (4)

Illinois (20)

Maryland (10)

Massachusetts (11)

New Jersey (14)

New Mexico (5)

Nevada (6)

New York (29)

Oregon (7)

Rhode Island (4)

Vermont (3)

Virginia (13)

Washington (12)

Washington, DC (3)