The Trump campaign on Wednesday sued to stop ongoing ballot counting in Pennsylvania, where President Trump holds a lead over Democratic nominee Joe Biden that is expected to narrow.

The campaign sought to intervene in a case pending before the Supreme Court that would invalidate a decision to count mail-in ballots received by Friday but that are postmarked by Election Day. The high court previously declined to fast-track the challenge from the state GOP, but could reconsider the case.

President Trump has been particularly fixated on the ballot deadline, attacking the Supreme Court for refusing to strike down the extension and baselessly claiming it would "induce violence." He has expressed hope the high court may reconsider.

In the interim, the campaign filed suit to temporarily halt the ballot count until Republican poll observers are given increased visibility into the ballot counting and tabulation.

The Keystone State still has roughly 1 million votes that have yet to be counted, but Trump officials sought to intervene while the president remained ahead.

In addition, the campaign accused accused Pennsylvania Secretary of State Kathy Boockvar (D) of improperly providing an extension for first-time voters to provide proper proof of identification in order for their vote to count.

"Without our action, Pennsylvanians, and possibly all Americans, may be forced to wait yet another several days for the outcome of the election – all because of the Secretary’s ridiculous eleventh-hour guidance that directly violates the Election Code," deputy campaign manager Justin Clark said.

The Trump campaign for weeks signaled it would take legal action in the event of a close race. The campaign requested a recount in Wisconsin, where Trump is trailing Biden by roughly 20,000 votes, and it filed separate litigation in Michigan seeking a pause in the vote count on the grounds that the GOP did not have proper visibility of the process. Trump is trailing in Michigan by roughly 37,000 votes.

Trump is leading in Pennsylvania by about 300,000 votes, but there are still hundreds of thousands of votes waiting to be counted, many of them coming from Democratic strongholds. Experts have said it is possible Biden could overtake Trump in the Keystone State once all the votes are counted.

The president must win Pennsylvania in order to win reelection, along with either Wisconsin, Michigan or Arizona. He is trailing in all three states, and Arizona and Wisconsin have been called for Biden by media outlets.

The campaign sent multiple surrogates to Philadelphia on Wednesday afternoon to highlight its legal challenges in the state. Former Florida attorney general Pam Bondi and Trump's personal attorney, Rudy Giuliani, were in the city to accuse Democrats of nefarious actions, though it is standard for states to continue counting ballots beyond Election Day.

Shortly after filing the lawsuits, campaign manager Bill Stepien declared victory in Pennsylvania on a call with reporters. White House press secretary Kayleigh McEnany and Eric Trump did the same on social media, but the president has not, in fact, won the Keystone State. Pennsylvania officials have said a final tally is likely to be completed by the end of the week.