Associated Press has called Arizona for Joe Biden
The state has not voted for a Democrat since Bill Clinton, but has been moving steadily towards Democrats in recent elections.
Pundits have speculated that voters in Arizona were particularly put off by Donald Trump’s animus towards the late John McCain.
At the current count, Mr Biden is ahead of Mr Trump in Arizona by five percentage points.
Millions of votes remain uncounted around the country.
– Donald Trump’s claim to have won the election is not being supported by even the most ardently conservative figures in the US.
Ben Shapiro, one of the most prominent conservatives on social media, immediately rebuked Mr Trump following his speech.
“No, Trump has not already won the election, and it is deeply irresponsible for him to say he has,” Mr Shapiro said.
Republican election lawyer Ben Ginsburg said there was “no natural path” for the president to appeal to the Supreme Court (SCOTUS).
“This would be viewed by any court and SCOTUS as massive disenfranchisement by the President,” he said.