Biden and his wife Doctor Jill Biden were at the Korean War Veterans Memorial at Penn's Landing in Philadelphia.
Biden made no comment, but took time to meet with veterans and pose for a quick photo.
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In a statement, Mayor Jim Kenney - whose team invited the Bidens to the city - said in part:
"I'm honored that President-elect Biden and Dr. Jill Biden chose to join us in Philadelphia on this important day of remembrance. I expressed that the City of Philadelphia stands by to support his administration, and we look forward to working together on our many shared priorities."
The visit comes after his remarks from his makeshift headquarters in Wilmington, Delaware about the president's refusal to concede the election.
Delaware Senator Chris Coons, an ally of the president-elect, says his challenge has been getting some of his Republican colleagues to acknowledge Biden's victory to help with the transition and policy.
"I've had a lot of conversation literally today and over the last three days with my colleagues about how we can pass a COVID relief package," Coons said.
Meanwhile, President Trump made his first public appearance in days to observe Veterans Day. Trump laid a wreath at the Tomb of the Unknown Soldier at Arlington National Cemetery.
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He did not make any comments.
The president continued his, so far, baseless allegations of widespread voter fraud through social media posts and pursuing legal action against counties in Pennsylvania.
Voters say they are concerned there may be no peaceful transition of power.
"Not saying President Trump didn't do a great job, but it's always good to have fresh eyes especially going on with this pandemic," said Greg Webb of New Castle.
"Whatever legacy he had, I think what he's doing right now is acting immature and I think it's not good for him, good for country, it's not good for any of us right now," added Johnathan Nere of Wilmington.
The State Elections Commissioner tells Action News the First State certified its election results Tuesday, so far officially declaring Biden the winner of the state.