Massachusetts Senator Elizabeth Warren, once a front-runner in the race for the Democratic presidential nomination, ended her campaign on Thursday, setting up a two-man duel between Joe Biden and Bernie Sanders.
"I'm suspending our campaign for president," the 70-year-old progressive lawmaker said in remarks to her campaign staff.
"I may not be in the race for President in 2020, but this fight - our fight - is not over," Ms Warren said.
"And our place in this fight has not ended."
Ms Warren did not announce any immediate plans to endorse either of the remaining major candidates - the 77-year-old former vice president Biden, or the 78-year-old leftist senator from Vermont, Sanders.
Ms Warren had planned to hold a press conference at 12:30 pm (1730 GMT).
Ms Warren's withdrawal from the race for the top spot on the Democratic ticket against President Donald Trump in November comes after she failed to win a single state on Super Tuesday, including her own.
Her decision to drop out comes one day after that of billionaire former New York mayor Michael Bloomberg, who quit on Wednesday after a disappointing Super Tuesday performance and endorsed Mr Biden.
President Trump responded to Ms Warren's withdrawal with a tweet mocking her and Mr Bloomberg.
"Elizabeth 'Pocahontas' Warren, who was going nowhere except into Mini Mike's head, just dropped out of the Democrat Primary...THREE DAYS TOO LATE," Mr Trump said.
"She cost Crazy Bernie, at least, Massachusetts, Minnesota and Texas," the president said of three of the states at stake on Super Tuesday.
"Probably cost him the nomination! Came in third in Mass."
She led some national polls last summer but she never managed to build a broad coalition to carry her through to success in the primaries, finishing behind fellow progressive Mr Sanders and the moderate Mr Biden in 14 states on Super Tuesday.
Ms Warren finished third in her home state of Massachusetts behind Mr Biden and Mr Sanders.
