Republican presidential nominee, former U.S. President Donald Trump participates in a Fox News Town Hall with Sean Hannity at the New Holland Arena in Harrisburg, Pennsylvania. AFP
Ahead of Tuesday's showdown against Republican rival Donald Trump in Philadelphia, Harris will head to Pittsburgh, where she will strategize with advisors and hone her attack lines, The Washington Post and CNN reported.
She does not have campaign events scheduled, but is expected to take part in informal meetings with voters.
Harris's entry into the race six weeks ago turbocharged enthusiasm among Democrats who were despondent about President Joe Biden's chances against Trump -- but both parties are bracing for a close election on November 5.
Pennsylvania, Georgia and a handful of other swing states are expected to be decisive and polls show most of those races within the margin of error.
The debate -- marking the beginning of the most intense phase of the campaign -- will be the first ever meeting between Harris and Trump, as the former president refused to attend Biden's inauguration after falsely claiming he was cheated in the 2020 election.
Harris's Pennsylvania huddle mirrors Biden's week-long preparation at Camp David in Maryland for his calamitous June 27 debate with Trump, which effectively ended his presidential campaign.
She has enlisted "House of Cards" consultant Karen Dunn, who led debate prep for Barack Obama in 2012 and Hillary Clinton in 2016, as well as top policy advisor Rohini Kosoglu.
Trump, 78, has said he is preparing, as he did against Biden, through speaking engagements on the campaign trail and policy discussions with a tight circle of aides.
During a Fox News town hall on Wednesday in Pennsylvania, the Republican baselessly accused debate host ABC of bias, called the network and one of its star anchors "nasty", and made unfounded claims that Harris would be shown the debate questions in advance.
"They're very nasty, and I think a lot of people are going to be watching to see how nasty they are, how unfair they are," Trump complained.
On Thursday, he will speak remotely to a gathering of the Republican Jewish Coalition in Las Vegas and in person at the Economic Club of New York.
The vice president was last in Pittsburgh on Monday, where she visited union members with Biden and echoed his opposition to the sale of US Steel to Japan's Nippon Steel.
US Steel sealed a $14.9 billion agreement for the sale in December but the transaction has faced an avalanche of political opposition following its condemnation by the United Steelworkers union.
The company warned Wednesday it could shut its headquarters and factories in Pennsylvania if the takeover is blocked.
Supporters of the deal touted the transaction as a lifeline to one of western Pennsylvania's defining industries.
Trump has also vowed to block the deal, while his running mate J.D. Vance has led congressional opposition to the takeover, describing domestic steel production as a national security priority.
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