"Proud of all that @JoeBiden and his administration have accomplished these last few years. He's delivered for the American people — and he'll continue to do so once he's re-elected. Let's get to work!" Obama said, retweeting Biden's video announcement and including a link to Biden's campaign website. 

Biden on Tuesday officially declared his candidacy for reelection after saying for months that he intended to run.

In his announcement video, he touted his accomplishments and highlighted the Jan. 6, 2021, riot at the U.S. Capitol and protests after the Supreme Court overturned Roe v. Wade.

"When I ran for president four years ago, I said we are in a battle for the soul of America — and we still are," Biden says in the video. "The question we are facing is whether in the years ahead we have more freedom or less freedom, more rights or fewer."

But Biden is mounting his bid at a time when voters have expressed misgivings about a potential Biden-Trump rematch.

Biden is running for reelection as the oldest sitting president in U.S. history, and some voters have expressed concerns about Biden's ability to serve as president for four additional years. 

Biden would be 86 years old at the end of his second term if he gets reelected. 

A Reuters-Ipsos poll taken just before Biden's announcement found that almost half of Democrats said they do not want him to run for reelection, and more than 60 percent of respondents said Biden is too old to serve. 

An NBC News poll published Sunday found 70 percent of Americans and 51 percent of Democrats don't think Biden should run for reelection in 2024. The same poll found 60 percent of Americans and roughly one-third of Republicans do not think Trump should run again.