Pennsylvania is among a handful of battleground states President Donald Trump and Democratic challenger Joe Biden are narrowly separated in vote totals.

News 12's Scott McGee is at the Philadelphia Convention Center where election personnel are counting tens of thousands remaining ballots from Philadelphia.

McGee says large crowds formed at the convention center to rally for the respective candidate.

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On one side is a group that labels itself as the "Count Every Vote" organization, and claims it is nonpartisan and just wants to make sure that every ballot is counted.

On the other is Trump supporters.

Trump, who held a 675,000-vote lead early Wednesday, prematurely declared victory in the state.

"We're winning Pennsylvania by a tremendous amount. We're up 690,000 votes in Pennsylvania. These aren't even close. It's not like, 'Oh, it's close,'" Trump said during an appearance at the White House.

State law prevented election officials from counting mail-in ballots until Wednesday. Since then, the president's once huge lead has slowly disappeared, leaving many Democrats feeling confident Pennsylvania could clinch the election for them.

By Thursday morning, his lead had slipped to about 136,000. And the race is destined to get tighter.

One reason: Under state law, elections officials are not allowed to process mail-in ballots until Election Day. It's a form of voting that has skewed heavily in Biden's favor after Trump spent months claiming — without proof — that voting by mail would lead to widespread voter fraud.

Mail ballots from across the state that were counted by late Wednesday overwhelmingly broke Biden's direction.

A final vote total may not be clear for days because the use of mail-in ballots, which take more time to process, has surged as a result of the coronavirus pandemic.

Democrats had long considered Pennsylvania a part of their "blue wall" — a trifecta that also includes Wisconsin and Michigan — that for years had served as a bulwark in presidential elections. In 2016, Trump won each by less than a percentage point.

Biden, who was born in Scranton, claims favorite-son status in the state and has long played up the idea that he was Pennsylvania's "third senator" during his decades representing neighboring Delaware. He's also campaigned extensively in the state from his home in Delaware.