Donald Trump will become the 45th US president after a stunning victory over Democrat Hillary Clinton.

The Republican nominee defied pre-election polling to claim swing states, winning the key battlegrounds of Florida, Ohio and Pennsylvania.

He told cheering supporters that Americans must now unite and "bind the wounds of division", after a gruelling, acrimonious campaign.

Global markets plummeted, with the US dollar diving and gold prices surging.

As poll counting went late into the night, it was Mr Trump's shock victory in Wisconsin that put him over the 270 out of 538 electoral college votes needed to win the White House.

The US president-elect took to the stage with his family at his victory rally in a New York hotel ballroom and said: "I just received a call from Secretary Clinton. She congratulated us on our victory.

"Hillary has worked very long and very hard over a long period of time, and we owe her a major debt of gratitude for her service to our country."

He added: "It is time for us to come together as one united people."

The real estate tycoon, former reality TV star and political newcomer, who was universally ridiculed when he declared his candidacy in June last year, said his victory had been "tough".