Biden campaign raises $26m in 24 hours after announcing Kamala Harris pick

Joe Biden’s Democratic presidential campaign raised $26m in the 24-hour period after he announced that Kamala Harris, the California senator, will be his running mate, a huge boost in funding for the ticket.

The amount was seen as a sign of strength and momentum behind Biden’s campaign brought on by Harris’ arrival. Donald Trump’s fundraising in July topped Biden’s by nearly $30m, bringing in a total of $165m compared with Biden’s $140m, but the former vice-president is closing the gap.

During a virtual grassroots fundraiser, Biden said that 150,000 donors were first-time contributors. “It’s really palpable, the excitement, because there’s so much at stake,” he said.

The fundraiser immediately followed Biden and Harris’ first joint campaign event in Wilmington, Delaware, on Wednesday, where the candidates said Trump had left the US “in tatters” because of his failed response to the Covid-19 pandemic and its economic fallout.

Related: If Kamala Harris wins, who might fill her California Senate seat?

“We have a president who cares more about himself than the people who elected him,” Harris said, in her first speech as the vice-presidential nominee.

“He inherited the longest economic expansion in history from Barack Obama and Joe Biden. And then, like everything else he inherited, he ran it straight into the ground,” she said.

If they prevail in November, Biden and Harris are likely to inherit a country still reeling from the pandemic that the Trump administration has failed to contain. Young protesters are demanding sweeping change to political and economic power as well as a governing agenda that addresses systemic racism, the climate crisis and economic inequality.

The pair were briefed by public health experts on the coronavirus crisis on Thursday.

The president’s campaign has launched a scattershot assault on Harris, attacking her as “radical” and leftwing, even though progressives in her party view her as more moderate. On Wednesday, Trump used his press briefing to attack Harris with language that nodded to America’s pejorative “angry Black woman” stereotype.

On Thursday he followed with a series of sexist attacks against Harris, calling her a “mad woman” and “extraordinarily nasty” when referring to her questioning of Trump’s intensely controversial US supreme court nominee Brett Kavanaugh during his confirmation hearing in 2018.

In an interview with Fox Business’s Maria Bartiromo on Thursday, Trump referred to Harris as “the angriest of the group” of Democrats who ran for president. Though she had initially been seen as a strong contender, Harris dropped out of the race in December.

Earlier on Thursday morning, Trump tweeted that the media had given Harris a “free pass” saying there was “nobody meaner or more condescending” to Biden during the primaries.

Trump’s tirade on Fox Business also included the New York congresswoman Alexandria Ocasio-Cortez, saying that she “is not even a smart person” and that she “goes out and yaps”. Trump also described the House speaker, Nancy Pelosi, as “stone-cold crazy”.

Biden had struggled to keep pace with his Democratic rivals in fundraising during the primary race but quickly grew his finance operation for the general election. Harris is known as a successful fundraiser, and already helped raise millions of dollars for the Biden campaign before she was named as his running mate.

Harris will deliver her much-anticipated speech for the Democratic national convention next week at the Chase Center in Wilmington. The convention has been totally upended by the coronavirus pandemic. It has been dramatically scaled back and is to be held almost entirely virtually, with speakers such as Bernie Sanders, Elizabeth Warren, Alexandria Ocasio-Cortez and the Obamas slated to make appearances. Biden will formally accept the Democratic presidential nomination on Thursday night.

The national conventions are usually some of the main events of the presidential election, marking the official end of the primaries and gearing the party toward the general election.

Lauren Gambino contributed to this report