ATLANTA — Election officials in several key states furiously counted ballots Wednesday as the nation awaited the outcome of the race between President Donald Trump and Democrat Joe Biden and braced for possible recounts and legal challenges.

Unlike in previous years, states were contending with an avalanche of mail ballots driven by the global pandemic. Every election, what’s reported on election night are unofficial results and the counting of votes extends past Election Day. This year, with so many mail ballots and close races in key states, counting every vote was expected to take more time.

Here’s what was happening Wednesday in six key states:

GEORGIA

Georgia Secretary of State Brad Raffensperger said he was pushing counties to complete vote tallies by the end of Wednesday, with roughly 200,000 ballots left to count as of late morning.

There was a narrow margin between Trump and Biden in Georgia, a close race in a state that has not backed a Democrat for president since 1992. There is no automatic recount, but a candidate can request one if the margin is within 0.5%.

“My team has sent reminders to counties to get all, let me repeat, all of our results counted today. Every legal vote will count,” Raffensperger said.

The outstanding vote was primarily in the Atlanta area, which tends to lean Democratic. On Wednesday, about 50 people were counting votes inside State Farm Arena, the home of the Atlanta Hawks NBA team. Counties have until 5 p.m. on Nov. 13 to certify results.

At stake in Georgia are 16 electoral votes. All absentee ballots were due Tuesday.

MICHIGAN

In Michigan, at least 100,000 ballots had yet to be counted as of around noon, according to Secretary of State Jocelyn Benson. Many were in Democratic cities including Detroit, Grand Rapids, Flint and Kalamazoo.

“These ballots were cast by tens of thousands of Michigan citizens who have the right to have their vote counted. We’re going to make sure that right is protected,” Benson said.

She asked for patience and expressed optimism the state could have most if not all votes counted by the end of the day.

On Wednesday, Trump’s campaign filed a lawsuit seeking to halt the vote count. Campaign manager Bill Stepien said the campaign had not been provided with “meaningful access” to observe the opening of ballots and the counting process in numerous locations.

At stake in Michigan are 16 electoral votes. All absentee ballots were due Tuesday.

NEVADA

Nevada was not expected to release a new batch of results until Thursday morning.

State election officials said early Wednesday that mail-in ballots received on Election Day had not yet been counted and were not included in unofficial results showing Biden with a slim lead over Trump. In addition, ballots would continue to be accepted if they were postmarked by Tuesday.

The number of outstanding mail ballots is difficult to estimate because Nevada opted to send ballots to all 1.7 million active registered voters this year due to the pandemic, and it’s hard to predict how many will choose to return them.

At stake in Nevada are 6 electoral votes. All mail ballots are due Nov. 10 if postmarked by Election Day.

NORTH CAROLINA

Election officials were working through any last-minute ballots that arrived Wednesday and would continue to process and count those delivered by the Postal Service through Nov. 12, as long as they were postmarked by Election Day.

Counting of all votes was complete, and Trump held a narrow lead over Biden.

The state board had extended the deadline for absentee ballots to be received at local election offices from Nov. 6 to Nov. 12 as part of a consent decree in a state lawsuit by voting rights advocates. They must be postmarked by Election Day.

At stake in North Carolina are 15 electoral votes.

PENNSYLVANIA

An estimated 1 million ballots have yet to be counted in Pennsylvania.

State election officials had warned repeatedly in the lead up to Election Day that it would take days to count because of a massive surge in absentee ballots brought on by the pandemic and a recent change in state law that meant an excuse was no longer needed to vote absentee. Slowing the process down was the fact that local election officials could not begin processing and scanning ballots ahead of Election Day, as most states did.

On Wednesday, Philadelphia aired live video of workers in yellow and orange safety vests preparing ballots to be scanned. City officials counseled patience.

“Counting votes cast by mail, if you’re going to do it right and you’re going to do it accurately — because there’s no other choice — takes a little bit of time,” City Commissioner Al Schmidt said. “It’s more important that we do it right than meet artificial deadlines.”

A lingering question is what will happen to mail ballots that arrive after Election Day. State law allows for these ballots to be counted so long as they are received by Nov. 7. But Trump has railed over several days about the U.S. Supreme Court’s refusal to rule out those ballots ahead of the election and said he’d go in “with lawyers.”

“This is an hour by hour, maybe minute by minute situation in Pennsylvania,” said Suzanne Almeida, interim executive director of Common Cause Pennsylvania. “We will be prepared, however, to do whatever we need to to make sure every eligible vote gets counted.”

At stake in Pennsylvania are 20 electoral votes. All absentee and mail ballots are due Nov. 6 if mailed by Election Day.

WISCONSIN

The Associated Press called Wisconsin for Biden on Wednesday afternoon, and Trump’s campaign promised to seek an immediate recount.

All ballots had been counted with the exception of 300 votes outstanding from one township and an unknown number of uncounted provisional ballots, likely fewer than 1,000 based on prior elections.

The Associated Press called the state for Biden on Wednesday afternoon, and Trump’s campaign promised to seek an immediate recount, citing “reports of irregularities in several counties.”

Biden’s lead was roughly 20,000 votes, or about six-tenths of a percentage point, and within the state’s 1-point margin for recounts.

Meagan Wolfe, the state’s top elections official, did not directly address the Trump campaign’s claim of irregularities. Instead, Wolfe defended the state’s voting processes, noting a recount of the 2016 presidential result showed no widespread problems and resulted in only a few hundred votes changing.

“There are no dark corners or locked doors on elections,” Wolfe said. “Anybody was free to watch those processes yesterday.”

At stake in Wisconsin are 10 electoral votes. All absentee ballots were due Tuesday.

AP reporters from around the country contributed to this report.