Explainer: A closer look at key battleground Arizona

State officials say there are about 450,000 votes still to be counted in Arizona, a Western presidential battleground state, where Democrat Joe Biden has a 2.35 percentage points lead over Republican Donald Trump, an advantage of about 68,000 votes.

The Associated Press news agency has called the race in Arizona for Biden. Fox News has also projected Biden to win the race in Arizona, but other US media outlets have yet to issue a projection there amid continuing ballot counting. The AP said on Thursday it is monitoring the vote count in the state as ballots continued to be tallied.

“The Associated Press continues to watch and analyse vote count results from Arizona as they come in,” said Sally Buzbee, AP’s executive editor. “We will follow the facts in all cases.”

The vast majority of the ballots still being counted are from Maricopa County, the most populous area of the state. The next update from elections officials in Arizona is expected about 9pm EST on Thursday (02:00 GMT on Friday).

The Trump campaign says it is confident the president will overtake Biden when all votes in the state are tallied.

The AP called the race in Arizona for Biden at 2:50am EST (07:50 GMT) on Wednesday after an analysis of ballots cast statewide concluded Trump could not catch up in the ballots left to be counted.

Arizona has a long political history of voting Republican. It is the home state of Barry Goldwater, a five-term, conservative senator who was the Republican nominee for president in 1964. John McCain, the party’s 2008 presidential nominee, represented the state in Congress from 1983 until his death in 2018.

But changing demographics, including a fast-growing Latino population and a boom of new residents — some fleeing the skyrocketing cost of living in neighbouring California — have made the state friendlier to Democrats.

Many of the gains have been driven by the shifting politics of Maricopa County, which is home to Phoenix and its suburbs. Maricopa County accounts for 60 percent of the state’s vote, and Biden leads there by 4.2 percentage points in votes that have already been tabulated.