Joe Biden is already projected to win the US presidential election, according to major US media. But all outlets have yet to project a final winner in four US states, as of Monday: Alaska, Arizona, Georgia and North Carolina.
Biden needs at least 270 votes in the Electoral College, which ultimately decides the presidency. Those 538 votes are apportioned among the states and chosen in individual state contests on Election Day, usually on a winner-take-all basis.
Biden currently has at least 279 electoral votes. Republican incumbent President Donald Trump has only 214 -- even if he wins all four remaining states, he cannot reach 270.
Biden has received 49.5 per cent of the vote, compared to 49 per cent for Donald Trump -- a narrow margin of 16,985 votes, with 98 per cent of ballots counted.
Fox News and the Associated Press (AP) called the race in the western state in the Democrat's favor on Election Night, triggering Trump's wrath.
Other media, such as The New York Times and CNN, have so far refrained from declaring a winner in Arizona, a traditionally Republican bastion.
More than 98 per cent of the votes have been counted in this southeastern state, which has consistently voted Republican since 1996.
Trump's initial lead dissipated as mail-in votes were counted in major urban areas such as Atlanta, and Biden has overtaken him.
The Democrat currently has a lead of more than 10,350 votes, according to state election data.
Some 98 per cent of the votes have been counted in this traditionally Republican southeastern state.
At the moment, Trump is ahead of Biden by about 75,000 votes, with a total of about 50 per cent of the vote versus his rival's 48.6 per cent.
Only 56 per cent of the votes have been counted in Alaska, due to the complicated logistics of collecting ballots in the vast state, and cross-referencing absentee ballots to ensure no one voted twice.
Trump leads with 62.9 per cent of the count so far. No Democrat has won in Alaska for decades.
If Biden wins Arizona and Georgia, as some projections suggest, he will have 306 of the 538 electors -- the same number that propelled Trump to victory in what the president has called a "landslide" over Hillary Clinton in 2016.