Joe Biden may have yet to announce his reelection campaign formally, but he made it clear on Friday that he intends to seek a second term as US President.

"My intention is... has been from the beginning, to run," he told ABC news in a sit-down interview.

He was asked about his plans after his wife, Jill Biden, said in a separate interview that her husband would run again and that there's "pretty much" nothing left to do but figure out the time and place for the announcement.

"How many times does he have to say it for you to believe it?" the first lady told The Associated Press during a visit to Kenya.

No rush to start campaigning

However, Biden said he was in no hurry to formalize his candidacy.

"There's too many other things we have to finish in the near term before I start a campaign," he said. "I've got other things to finish before I get into a full-blown campaign."

At 80, Biden is the oldest sitting president, and he would be 86 at the end of a second term, should he gain reelection.

Although he was declared fit for his role earlier this week, there have been questions about whether he is too old to run for another term.

"It's legitimate for people to raise issues about my age. It's totally legitimate to do that."

"The only thing I can say is 'watch me,'" he added, referring to his record in office.

Republican opponents started campaigning

Poll results published by NPR/PBS NewsHour/Marist Poll shows half of Democrats or Democratic-leaning independents think their party has a better chance of winning the White House in 2024 with Biden as its nominee.

That is in contrast to a poll released by the Associated Press-NORC Center for Public Affairs Research earlier this month which found just 37% of Democrats wanted him to seek a second term.

Thursday's poll results, however, put Biden in a better place than former President Donald Trump, who announced his candidacy in November last year. It found 54% of Republicans and Republican-leaning independents say the GOP has a better chance of winning the presidency in 2024 with someone other than Trump as the party's nominee.

Nikki Haley, a former governor of South Carolina turned US ambassador to the UN under Trump, announced last week that she was running to secure the Republican nomination for president in 2024.

Florida Governor Ron DeSantis and former Vice President Mike Pence have also been touted as potential nominees for the Republican party.