Democratic presidential candidate Beto O'Rourke shakes hands as he arrives at a packed St. Patrick's Day party at the home of County Recorder John Murphy March 16, 2019 in Dubuque, Iowa.

WASHINGTON — Beto O'Rourke raised $6.1 million in his first 24 hours as a presidential candidate, according to his campaign, surpassing Bernie Sanders and every other 2020 Democrat who has disclosed their figures.

O'Rourke's campaign announced Monday that he had taken in $6,136,763 in online contributions in the day after declaring his candidacy Thursday morning.

"In just 24 hours, Americans across this country came together to prove that it is possible to run a true grassroots campaign for president — a campaign by all of us, for all of us, that answers not to the PACs, corporations, and special interests but to the people," O'Rourke, who has sworn off PAC donations of any kind, said in a statement.

That's a strong showing for the former Texas congressman who lost a Senate race last year to Republican Sen. Ted Cruz, while setting a new fundraising record.

Sanders beat expectations and stunned observers by raising a then-record-setting $5.9 million in his first 24 hours as a candidate last month.

Meanwhile, Sen. Kamala Harris collected $1.5 million, which was seen as impressive haul for the California Democratic lawmaker. Sen. Amy Klobuchar, D-Minn., raised $1 million in 48 hours, as did former Colorado Gov. John Hickenlooper. It took Jay Inslee 72 hours to raise more than $1 million, but that still surpassed expectations for the Washington governor.

Sen. Elizabeth Warren, D-Mass., raised at least $300,000 on New Year's Eve, her first partial day in the race, according to filings from the online donation clearinghouse ActBlue. But her campaign declined to disclose their complete one-day fundraising picture.

The other Democratic candidates in the crowded field have not released their one-day hauls and are not required to disclose anything about their finances until the end of this month, when they make their first disclosure to the Federal Election Commission and the public.