Challenger Andy Kim took the lead over U.S. Rep. Tom MacArthur in the contest for New Jersey's 3rd Congressional District.

With mail-in and provisional votes still being counted, Democrat Kim pulled ahead of the Republican incumbent by 2,622 votes as of Wednesday afternoon, according to results posted by Burlington and Ocean counties.

UPDATE: Andy Kim: Victory is 'reality of the situation' even as ballot counting continues

UPDATE: Andy Kim declares victory, but Tom MacArthur not conceding

Kim held 148,580 votes while 145,958 people voted for MacArthur, the Wednesday afternoon results showed.

That reversed the lead MacArthur had held over his opponent overnight Tuesday.

Kim's campaign manager Zack Carroll said shortly after midnight Tuesday that tens of thousands of votes remain to be counted, including many from Kim's stronghold in Burlington County. See Kim address his supporters in the video above.

"We are confident that when all the votes are properly counted, Andy will be declared the winner," Carroll said.

MacArthur didn't make a public statement Tuesday night.

As of Wednesday morning, there were 6,000 mail-in ballots and an unknown number of provisional ballots — issued when a voter’s right to vote at the polls was questioned or uncertain — that had yet to be counted in Burlington County, according to Joseph Dugan, chairman of the board of elections in Burlington County.

George R. Gilmore, chairman of the bipartisan Ocean County Board of Elections, who is also the influential county Republican chairman, said the election panel would convene on 11 a.m. Friday to assess the status of the ballot count in Ocean County.

On Wednesday, the county received 250 mail-in ballots that were postmarked on or before Election Day and will continue to accept such ballots postmarked by Tuesday through Thursday, Gilmore said.

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There were between 1,500 and 2,000 provisional ballots which have to be reviewed by election officials and if necessary, the courts to determine eligibility, Gilmore explained.

This process could take weeks, even months, he said.

However, Gilmore said he hoped that the election would be resolved by the time the new Congress was seated in January.

Election officials in both counties said the review process for the provisional ballots was being handled behind closed doors at this time and would not be open to the public. Gilmore said the election board meeting on Friday would be open to the public.

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MacArthur was trying to give New Jersey Republicans a rare victory on a night that saw Democrats keep its Senate seat and gain three seats in the House of Representatives. His district of Ocean County and Burlington County seems to be a microcosm of a deeply divided America.

MacArthur, a 58-year-old former insurance executive from Toms River who spent $5 million of his own money winning the seat four years ago, became the most reliable New Jersey vote for Trump policies during the current Congress. He helped revive a stalled effort to repeal the Affordable Care Act and cast the only Garden State vote for the tax overhaul enacted in December.

Kim, 36, of Bordentown, is a Rhodes Scholar who served as a national security aide during the administrations of presidents George W. Bush and Barack Obama. He used the health insurance and tax votes to attack MacArthur, while promising to hold monthly in-person town hall meetings if elected.