WASHINGTON - The White House on Friday addressed a fresh round of questions about President Joe Biden's ability to run for reelection given his age with a one-liner: "80 is the new 40."

Biden, 80, already the oldest American president ever, is running for re-election in 2024 and would be 82 when his second four-year term begins in January 2025 if he wins.

A variety of polls show concerns among voters about Biden's age, and that of his top Republican challenger, Donald Trump, 77. The latest Reuters/Ipsos poll shows Democrat Biden tied in a hypothetical 2024 election against Trump, the former president. Both received 39% of the vote with one in five voters undecided.

Most Americans would prefer the cutoff for running for president to be 75 or younger, an earlier Reuters/Ipsos poll shows.

Asked about concerns the president would be too old run for reelection, White House press secretary Karine Jean-Pierre quipped, "80 is the new 40, didn't you hear?"

"In 2019, he got the same criticism, in 2020, he got the same criticism, in 2022 he got the same criticism and every time he beats the naysayers," Jean-Pierre said.

(Reporting By Steve Holland; Editing by Heather Timmons and Timothy Gardner)