Biden said he would speak to the matter further later this week.
His decision, made after weeks of growing pressure from members of his own party, throws Democrats into uncharted territory.
Sen. Joe Manchin, an independent from West Virginia who caucuses with Democrats, called for an "open process" to select a new nominee as he called for Biden to step aside earlier on Sunday.
On Sunday, immediately after Biden announced his decision to withdraw, a series of Republican politicians called on Biden to resign immediately, including Speaker Mike Johnson.
"If Joe Biden is not fit to run for President, he is not fit to serve as President," Johnson said.
Persons:
—, Joe Biden, Biden, Kamala Harris, I've, Harris, Donald Trump, Sen, Joe Manchin, Gretchen Whitmer, Cory Booker of, There's, Alexandria Ocasio, Cortez, Joe Biden doesn't, J.D, Vance, @JDVance1, Mike Johnson, Johnson
Organizations:
Service, Business, Democratic, Democratic National Committee, Michigan, Cory Booker of New, Rep, Republicans, Biden
Locations:
Chicago , Illinois, West Virginia, Cory Booker of New Jersey, Alexandria, Cortez of New York