Biden responded Tuesday to the president's attack in a fundraising email.
"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," the fundraising email said.
(MORE: Joe and Jill Biden respond to women who say he made them uncomfortable) Additionally, KCNA mocked him for falling asleep during a budget speech former President Barack Obama made in April 2011.
KCNA also hit Biden for withdrawing from the 1988 presidential campaign after reports of plagiarism arose. Biden used elements of a speech by a British politician as his own, without attribution. In an interview with ABC News in 2007, Biden described the scandal as "Stupid. My mistake. Born out of ignorance, thinking I didn't have to prepare."
North Korea cautioned the former vice president that language on the campaign trail matters.
"Biden should remember, as someone who failed in a presidential run twice, that he should be careful with his words, and that should be a basic quality of a presidential candidate," according to KCNA, which also warned it "will not forgive anyone who offends the dignity of our Supreme Leader and we will keep score to the very end."
ABC News' Molly Nagle and Paul Shin contributed to this report.
Kaynak:Abcnews