Ballots will continue to be counted Thursday in the extremely tight Democratic congressional primary race in Massachusetts' fourth district after a judge allowed additional votes to be counted that had been received on time but still not tallied.

As of Wednesday evening, the two front-runners seeking the opportunity to replace outgoing Rep. Joe Kennedy were separated by less than 1,500 votes, with former Newton City Councilor Jake Auchincloss leading former Brookline Select Board member Jesse Mermell. Mermell had a 105-vote lead when Wednesday's counting began, according to Patch.com.

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The primary was held on Tuesday, Sept. 1, but according to Secretary of the Commonwealth William Galvin, roughly two-thirds of the 1.5 million votes cast came via mailed absentee ballots.

The ballot count is taking place as President Trump claims the election results won't be fair with universal mail-in voting, while Democratic presidential nominee Joe Biden defends voting by mail as "the most secure form of voting."

Without existing Massachusetts laws governing how to deal with counting votes after Election Day, Galvin filed a petition in Superior Court.

"On Election Day, there are strict procedures in place to make sure that ballots are counted in public view, where anyone may observe the process," Galvin said in a statement upon seeking authorization from the court to keep counting. "It is important that we preserve that same level of transparency for ballots counted after Election Day.”

With the court allowing the count to continue, the race remains too close to call. Mermell's campaign supported Galvin's call for a transparent process.

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"This is exactly in line with the concerns our campaign raised earlier today," campaign manager Katie Prisco-Buxbaum said, according to Patch. "Given the unprecedented nature of this election process, we believe it is incumbent on all communities to be clear about how many ballots are outstanding, including ballots that arrived as polls closed, so that we can have the utmost confidence in the end result."

In this Aug. 5, 2020, file photo, vote-by-mail ballots are shown in sorting trays at the King County Elections headquarters in Renton, Wash. (AP Photo/Ted S. Warren, File)

In this Aug. 5, 2020, file photo, vote-by-mail ballots are shown in sorting trays at the King County Elections headquarters in Renton, Wash. (AP Photo/Ted S. Warren, File)

Auchincloss remained confident that he will come out on top whenever the counting is complete.

"While the results of our primary are being calculated, I encourage all voters and candidates to allow the process to comprehensively and lawfully unfold," he said. "While we always expected a competitive race, we are confident that our full-district campaign will be victorious when the results are announced."

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State rules allow for a recount if the difference between the two candidates is less than half a percent. Going into Thursday morning, Auchincloss is above that mark, having 22.37% of the votes to Mermell's 21.41%. Seven other candidates ran in the race, but none are in striking distance of the two leaders.

The winner will face off against Republican primary winner Julie Hall.