Election 2020 updates: Biden warns of 'dark winter,' pushes masks in pandemic plan

The margin between Trump and Biden in Georgia shrunk even more Thursday morning as thousands of additional votes were counted in Fulton County, the state's most populous county, which continues to process and tabulate ballots.

Trump now holds onto his lead in Georgia by just 18,540 votes. He has 49.6% of the vote -- 2,431,724 -- while Biden has 49.2% -- 2,413,184.

There are about 7,500 votes left to be counted in Fulton County. It's unclear how many remain outstanding statewide.

Military votes and overseas ballots must be received by Friday to be counted in Georgia's race, while provisional ballots must also be processed by Friday.

There are no mandatory or automatic recounts in the Peach State. A candidate may request a recount if they lose by less than 0.5% of total votes cast in the race. The deadline to request a recount is two business days after statewide election results are certified.

-ABC News' Quinn Scanlan

Election officials in Arizona's Maricopa County said early Thursday morning that they have an estimated 275,000 more ballots to process and tabulate.

With 86% of the expected vote reporting, Biden continues to lead in Maricopa County -- 51.4% to Trump's 47.2%. The county is Arizona's most populous and the fourth-most populous in the United States. The county seat is Phoenix, the capital of Arizona and one of the largest cities in the country by population.

Biden also holds an edge over Trump statewide, with 1,469,341 votes against Trump's 1,400,951 -- 50.5% to 48.1%. About 86% of the expected absentee vote and 86% of the expected vote overall are in.

In the Senate race, Democratic challenger Mark Kelly still leads incumbent Republican Sen. Martha McSally 52% to 48%. Kelly is currently outpacing Biden's vote statewide at 1,504,460 votes.

-ABC News' Meg Cunningham

Protests over the election turned violent in multiple cities across the country Wednesday night.

In Portland, Oregon, a riot was declared and the National Guard was activated due to violence downtown. At least eight people have been arrested, according to the Multnomah County Sheriff's Office.

In New York City, skirmishes broke out between police and protesters in Greenwich Village. The NYPD said more than 20 people were arrested in the violence.

"We appreciate and value the importance of freedom of speech. Our top priority is and always will be safety," the department said in a tweet. "We have arrested more than 20 individuals who attempted to hijack a peaceful protest by lighting fires, throwing garbage and eggs in Manhattan."

Protesters across the country called for officials to count every vote as President Donald Trump baselessly claimed current vote counts were fraudulent and filed lawsuits in several states to challenge vote totals.

Final results from North Carolina are not expected to come in until next week, ABC News correspondent Janai Norman reported. Currently, Donald Trump is leading in the state with about 76,000 more votes than Biden with 117,000 absentee ballots outstanding.

"If you're Joe Biden that's not a whole lot to be excited about," Norman said. "He did what he was expected to do in those heavily urban areas -- Raleigh, Durham, here in Charlotte -- but he wasn't able to really run up this or the suburbs."

"This isn't even a case of seeing a slow trickle, and those numbers fluctuating, going up in the next few days," she added. "They'll remain pretty steady until the 12th [of November] at the earliest, 13th at the latest."