Harris's campaign officially joined TikTok, and the first post already has more than 2.6 million views.

"Well I've heard that recently I've been on the 'For You Page,' so I thought I'd get on here myself," she said in the post.

Since President Biden's endorsement of Harris' candidacy, the @KamalaHQ account on TikTok has more than tripled (almost quadrupled) its following – growing from 440K followers to over 1.7 million followers.

But the campaign has faced criticism over its presence on TikTok after the Senate passed a bill that Biden signed into law requiring TikTok's Chinese parent company to sell or the app would be banned.

According to the measure, ByteDance must divest TikTok within a nine-month window from when the bill was signed into law in April.

In March, Harris responded to the criticism from TikTok users stating "We need to deal with the owner and we have national security concerns about the owner of TikTok, but we have no intention to ban TikTok."

-ABC News' Gabriella Abdul-Hakim, Fritz Farrow and Wil McDuffie

Several Black groups have responded to grassroots enthusiasm for Harris with new efforts to mobilize voters to the polls.

Quentin James founded Collective PAC, an organization that supports Black candidates at all levels of government around the country. James helped organize the Monday night Win with Black Men Zoom call -- telling ABC News that the call was just the beginning.

"As someone who's done a lot of fundraising, I've never raised $1.3 million over three or four hours from grassroots donors, I've never seen that kind of momentum," James said. "The energy is inspiring. Each one of those people on the call can organize 10 people or 100 people, and we hope to mobilize all of them."

-ABC News' Tommy Barone and Gabriella Abdul-Hakim

Former President Barack Obama officially endorsed Vice President Kamala Harris on Thursday to be the Democratic Party’s 2024 nominee, saying in a statement that she "has the vision, the character, and the strength that this critical moment demands."

"There is no doubt in our mind that Kamala Harris has exactly what it takes to win this election and deliver for the American people. At a time when the stakes have never been higher, she gives us all reason to hope," he added.

Obama was one of the only high-profile Democrats who had yet to endorse Harris.

-ABC News' Alexandra Hutzler

Former President Donald Trump's campaign is now claiming that it cannot commit to general election debate details until Democrats formally decide on a nominee.

"Given the continued political chaos surrounding Crooked Joe Biden and the Democrat Party, general election debate details cannot be finalized until Democrats formally decide on their nominee," Trump Campaign Communications Director Steven Cheung said in a statement.

Cheung's said Dems "are still holding out for someone 'better.' Therefore, it would be inappropriate to schedule things with Harris because Democrats very well could still change their minds."

Vice President Kamala Harris quickly responded on X, "What happened to 'any time, any place?'"

Trump previously committed to ABC News' debate on Sept. 10, along with invitations from CBS, NBC, and Fox.

This week, he has started to push for a debate hosted by Fox News.

On the campaign trail, Trump has stated that he wants to debate Harris and would be willing to do more than one debate.

-ABC News' Lalee Ibssa, Soo Rin Kim and Kelsey Walsh