Nevada is the latest state where the Trump campaign has launched legal action as his anger grows over votes being counted.
The move will be announced this morning by Ric Grenell, former acting Director of National Intelligence, claiming voter fraud.
The US President, after a 13 hour Twitter break, posted: "STOP THE COUNT!"
Trump's campaign is already trying to stop counting in Pennsylvania, Wisconsin, Georgia and Michigan as his grip on the White House appears to be slipping away.
It comes as an international watchdog said the US election process has been “tarnished by legal uncertainty and unprecedented attempts to undermine public trust”.
The Organization for Security and Co-operation in Europe (OSCE) branded the vote “competitive and well managed” - but said: “At the same time, the campaign was characterised by deeply entrenched political polarisation that often obscured the broader policy debate and included baseless allegations of systematic fraud”.
In a statement the OSCE mission said “baseless allegations of systematic deficiencies, notably by the incumbent president, including on election night, harm public trust in democratic institutions”.
Donald Trump branded the count a “massive fraud” and threatened to go to the Supreme Court. He has also launched lawsuits in states he is worried of losing.
In order to reach the 270 electoral college votes he needs to win, Trump must now win four remaining battlegrounds - Pennsylvania, North Carolina, Georgia and Nevada.
Bookies now have Biden - who last night called for unity and said he was confident of winning - with an 86% chance of taking over the White House.