Republican Donald Trump scored a series of shocking wins in battleground US states including Florida and Ohio on Tuesday, opening a path to the White House for the political outsider and rattling world markets that had counted on a win by Democrat Hillary Clinton.

With investors worried a Trump victory could cause economic and global uncertainty, the US dollar sank and stock markets plummeted in wild Asian trading. Opinion polls before Election Day had given Clinton a slim lead.

Mexico's peso plunged to its lowest-ever levels as Trump's chances of winning the presidency increased. Concerns of a Trump victory have weighed heavily on the peso for months because of his threats to rip up a free trade agreement with Mexico and tax money sent home by migrants to pay to build a wall on the southern US border.

Trump surged to wins in Florida, Ohio, Iowa and North Carolina, and Fox News projected a win for him in Wisconsin. With voting completed in 49 of the 50 US states, he also narrowly led in Michigan and New Hampshire, edging him closer to 270 Electoral College votes needed to win the state-by-state fight for the White House.

Shortly after Fox called Wisconsin for Trump, supporters at his election evening rally in New York began to chant "Lock her up" - a common refrain on the campaign trail for the former US secretary of state repeatedly dubbed "Crooked Hillary" by Trump.

Clinton still had ways to reach 270 electoral votes, but she would have to sweep the remaining battleground states including Pennsylvania, Michigan and Nevada, and pull off an upset win in Arizona.

Trump captured conservative states in the South and Midwest, while Clinton swept several states on the East Coast and Illinois in the Midwest.

After running close throughout the night in Virginia, Clinton pulled out the swing state that is home to her running mate, Senator Tim Kaine. But Trump