Vice President Harris is racing to lock down support for her White House bid, just hours after President Biden announced that he would no longer seek reelection.

Harris on Sunday spoke with the chairs of three key coalitions on Capitol Hill: Rep. Pramila Jayapal (D-Wash.) of the Congressional Progressive Caucus, Rep. Nanette Barragán (D-Calif.) of the Congressional Hispanic Caucus and Rep. Ann McLane Kuster (D-N.H.) of the New Democrat Coalition. All three have backed Harris for the nomination.

She also spoke with Rep. Mark Pocan (D-Wis.) — ”She is ready to win in Wisconsin!!!” he said on the social platform X — and Rep. Jared Huffman (D-Calif.) said he heard from her staff.

“Her team is fully activated and phones are ringing, emails are blowing up, this thing is rolling,” Huffman told The Hill in a brief interview Sunday. “This has taken off like a rocket ship.”

Asked what the sentiment of his conversation was, Huffman responded: “Let’s roll.”

The full-court press on Capitol Hill comes as Harris looks to turbocharge her nascent presidential campaign after Biden announced that he would no longer seek the party’s nomination.

Biden was facing mounting pressure from Democrats to reconsider his decision to run amid concerns following his disastrous debate performance last month. The president was at first defiant, consistently saying he would not step aside, but reversed his position on Sunday, quickly endorsing Harris for the job.

“My very first decision as the party nominee in 2020 was to pick Kamala Harris as my Vice President. And it’s been the best decision I’ve made,” Biden said on X. “Today I want to offer my full support and endorsement for Kamala to be the nominee of our party this year.”

Harris embraced the endorsement, writing in a statement: “I am honored to have the President’s endorsement and my intention is to earn and win this nomination.”

Harris is expected to maintain an aggressive travel schedule as she’s been doing in recent months, according to a source familiar with the matter. Major Democratic PACs, including AAPI Victory Fund, the Collective PAC and Latino Victory Fund endorsed her on Sunday, and the Biden campaign infrastructure is pivoting to support Harris.

Harris’s sprint to ramp up support comes less than one month before the Democratic National Convention is set to kick off in Chicago. A number of Democratic lawmakers have endorsed Harris for the nomination, but some key names are reserving judgment. Former Speaker Nancy Pelosi (D-Calif.), Senate Majority Leader Chuck Schumer (D-N.Y.), House Minority Leader Hakeem Jeffries (D-N.Y.) and former President Obama all heaped praise on Biden but stopped short of endorsing Harris, raising some eyebrows.

The path forward remains largely unclear. Democratic National Committee Chair Jaime Harrison on Sunday said “In the coming days, the Party will undertake a transparent and orderly process to move forward as a united Democratic Party with a candidate who can defeat Donald Trump in November.”

“This process will be governed by established rules and procedures of the Party,” he added. “Our delegates are prepared to take seriously their responsibility in swiftly delivering a candidate to the American people.”

Jayapal on Sunday said she told Harris on the call that she is “1000% in for her to be our President!”

“She has the smarts, the experience, the accomplishments and the agenda to lead us to victory in November. Let’s go!” she added on X.

Barragán echoed that sentiment, writing on X: “Just spoke to the Vice President to reiterate that I’m all in.”

“Please join me and support Vice President Kamala Harris with a contribution today!” she added.

Brett Samuels contributed.