Controversial tycoon Donald Trump appears on course to be the next president of the United States after victories in key battleground states.
Wins in the swing states of Florida, Ohio and North Carolina helped give Mr Trump a lead in the race to the 270 electoral college votes required to take the White House.
Hillary Clinton's hopes of becoming the first female president in US history were hanging by a thread with her chances of victory depending on a fightback in the handful of states yet to declare.
With eight of the 51 results still to come, the Republican had 244 electoral votes, with his Democratic opponent on 215.
Florida's 29 electoral votes represented a major boost to Mr Trump's chances of success, while Ohio is a bellwether state with a history of being won by the eventual election victor.
In an indication of the confidence in the Republican camp, a senior aide at his New York "victory party" said Mr Trump had won the fiercely fought presidential race.
Layne Bangerter, director of the Trump for President campaign in Idaho, told the Press Association: "I'm saying it's over. The voice of the people has risen up."
In a message which appeared to betray nervousness in the Clinton camp, the Democratic nominee thanked her supporters "whatever happens tonight".
"This team has so much to be proud of," she said. "Whatever happens tonight, thank you for everything."
Victories in Virginia and Nevada gave the Clinton campaign cause for hope, but her chances of following husband Bill into the White House now rest on strong showings in Michigan, Wisconsin and Pennsylvania.
International markets reacted nervously as Mr Trump's victory chances increased. Shares tumbled across Asia, while the dollar plunged against the Japanese yen and the Mexican peso also slumped.