Democratic presidential hopeful Pete Buttigieg raised $24.8 million in the second quarter of 2019, more than tripling his fundraising from the first quarter of the year and indicating his staying power in the race for the White House.

According to the campaign, the haul came from 294,000 donors — including more than 230,000 new donors — in the second quarter of the year. That means that more than 400,000 Americans have donated to Buttigieg since he began his campaign.

The campaign says that they currently have $22.5 million cash on hand, and that the donations came from all 50 states and 7 territories. The average contribution was $47.42.

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The South Bend mayor's second quarter filings are the largest announced cash haul of any 2020 Democratic presidential candidate so far. In mid-June, former Vice President Joe Biden indicated to a group of donors in New York City that his campaign had raised roughly $20 million since he announce his bid for president, but Biden's campaign has yet to release his second quarter totals.

Buttigieg's fundraising numbers also have him on track to participate in September's Democratic presidential debate, which has a 130,000 unique donor threshold. Other candidates — including a number of senators, governors and congressmen — are struggling to meet the requirement.

Buttigieg's fundraising has been sustained by a mix of grassroots appeals and high-dollar events across the country. The campaign has held multiple fundraisers in Los Angeles, San Francisco, Chicago, New York and Washington, D.C.

An invitation obtained by CBS News confirms Buttigieg will headline a July 6 event at the Nantucket home of businesswoman Heather Reisman and her husband, billionaire investor Gerry Schwartz. It will be followed by a "grassroots" fundraiser on Martha's Vineyard that evening. Tickets begin at $250 for the Nantucket event and $15 for the Martha's Vineyard one. Buttigieg will also have an event the Friday before in Provincetown, Massachusetts.

Other Democratic campaigns have taken notice of the mayor's fundraising prowess. Just last week, Sen. Bernie Sanders took aim at Buttigieg in a fundraising email, blasting him and Biden for meeting with wealthy donors. Sanders and Sen. Elizabeth Warren have both sworn off high-end fundraising events.

In the first quarter of 2019, Buttigieg raised more than $7 million after launching an exploratory committee on Jan. 23, 2019. His official campaign kick-off in April raked in more than $1 million in a matter of hours.

While Buttigieg is the first candidate to release his second quarter fundraising totals, all presidential candidates are required to file with the FEC by July 15.