We 'definitely could' know Pennsylvania's results by the end of the day, secretary of state says

The battleground state’s counties are ‘furiously at work’ counting the remaining 550,000 ballots, said Kathy Boockvar

Pennsylvania secretary of state Kathy Boockvar said on Thursday afternoon that we "definitely could" know the winner of the key battleground state by the end of the day.

Speaking to CNN's Jake Tapper, Ms Boockvar said there are approximately 550,000 ballots left to count across the commonwealth. She added that counties are "furiously at work" counting the remaining votes and said their process is "ahead of schedule."

"You know, I've been saying that we'll have the overwhelming majority counted by tomorrow, but it is looking like we'll have the overwhelming majority counted by today," Ms Boockvar said.

The largest number of outstanding votes remain the state's big population centers, she said, including Philadelphia and Pittsburgh.

President Donald Trump and former vice president Joe Biden are vying for Pennsylvania's crucial 20 electoral votes, which both campaigns see as critical to their chances of winning the US election. 

Mr Trump's lead over Mr Biden has been narrowing in the state as counties report mail-in ballot results. As of just before 3pm EST, Mr Trump was ahead by just over 100,000 votes.

The Trump campaign has called for a halt to vote-counting in Pennsylvania and is steadfastly challenging the state’s Supreme Court ruling that ballots postmarked by election day can be received by Friday and still be counted. Mr Biden's campaign, meanwhile, says they believe they will win the state by a "sizable" margin when all the votes are tallied.