(CNN) Joe Biden responded Tuesday to President Donald Trump's claim that the former vice president "deserted" Pennsylvania, a critical battleground state in the 2020 presidential election.

"Donald Trump tried to attack me at his campaign rally by saying I abandoned Pennsylvania," the Democratic presidential candidate wrote in a fundraising e-mail Tuesday. "Well folks, I've never forgotten where I came from. My family did have to leave Pennsylvania when I was 10 -- we moved to Delaware where my Dad found a job that could provide for our family."

At a campaign rally in Montoursville, Pennsylvania, on Monday, Trump warned voters that Biden "left" the state.

"And don't forget Biden deserted you. He's not from Pennsylvania. I guess he was born here, but he left you folks. He left you for another state," President Trump said.

Trump narrowly won Pennsylvania in 2016, becoming the first Republican to do so since 1988, which contributed to his overall victory over Democratic nominee Hillary Clinton.

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