Donald Trump has falsely and unilaterally claimed victory in the US Presidential election besides calling on-going vote counting a "major fraud."
In a speech at the White House, the President said: "We'll be going to the US supreme court. We want all voting to stop."
The President has repeatedly claimed without evidence that postal ballots - used in vast numbers in this election due to the Covid-19 pandemic - are vulnerable to fraud.
Recently he has been incensed by some states allowing postal votes to be counted that arrived up to three days after election day, as long as they were postmarked before polls closed.
Speaking to an election night party in the East Room of the White House, Trump said: "Millions and millions of people voted for us tonight and a very sad group of people is trying to disenfranchise those people and we won't stand for that.
"We were getting ready for a big celebration. We were winning everything and all of a sudden it was all called off.
"We were ready to get outside and celebrate our incredible success."
He listed a string of states, including Georgia and North Carolina, where votes are still being counted - and falsely claimed he had already won them.
"You know what happened? They knew they couldn't win and they said let's go to court," he said.
"This is a fraud on the American public. This is an embarrassment to our country. we were getting ready to win this election, frankly we did win this election.
"So our goal now is to ensure the integrity for the good fo this nation. This is a fraud on this nation."
He added: "We will win this and as far as I'm concerned we already have won it."
Joe Biden called for patience from the American people as counting in the US election looked set to continue into a second day.
The frontrunner said his campaign was "on track to win this election."
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But he said the unprecedented level of early voting and mail in voting meant it would "take a while."
Speaking at his campaign HQ in Delaware, Biden said: "We feel good about where we are. We really do.
"I'm here to tell you tonight we believe we're on track to win this election. We knew because of the unprecedented early vote and mail-n vote, it was going to take a while and we'd have to be patient...and it ain't over til every vote is counted.
"But we feel good about where we are."
He added: "We could know the results as early as tomorrow morning, but it may take a little longer.
"It's not my place or Donald Trump's place to decide the outcome of this election. That's down to the American people."