Former President Barack Obama has also endorsed Vice President Harris.
Vice President Kamala Harris wrapped up what has been a whirlwind week in the presidential race with her campaign saying Sunday it has raised more than $200 million in less than a week.
On Thursday night, Harris met with Israeli Prime Minister Benjamin Netanyahu and took the lead in addressing the public about their discussions.
Harris has secured commitments from enough delegates to become the presumptive nominee if they all honor their commitment when voting, according to ABC News reporting.
Minnesota Gov. Tim Walz, who is also the co-chair of the DNC's rules committee and the chair of the Democratic Governors Association, voiced his support for Kamala Harris in an X post on Monday.
"Thanks for the call, @KamalaHarris. You have my full support," Walz wrote. "Let's go win this thing."
Sen. Dick Durbin, the Senate's No. 2 Democrat, publicly endorsed Harris Monday morning.
"I'm proud to endorse my former Senate colleague and good friend, Vice President Kamala Harris. Our nation needs to continue moving forward with unity and not MAGA chaos," Durbin wrote in a statement.
"Vice President Harris was a critical partner in building the Biden record over the past four years. Count me in with Kamala Harris for President," Durbin added.
-ABC New's Allison Pecorin
Maryland Gov. Wes Moore endorsed Harris for the top of the Democratic ticket on Monday.
In a post on X, Moore said "Today, I am proud to voice my full support and offer my full endorsement to Vice President @KamalaHarris to be the Democratic Nominee for President of the United States."
The governor, a Democrat, issued a statement on Sunday praising Biden for his decades of service.
"President Biden has dedicated his life and career to serving the American people," Moore wrote. "His legacy of hard work, dedication, optimism, and strength have shaped the trajectory of our nation -- and made us better as a people and as a country."
-ABC News' Tommy Barone and Sarah Beth Hensley
Independent Sen. Joe Manchin, who sources had told ABC News was considering re-registering as a Democrat to run for the presidential nomination, said on Monday he is not going to be campaigning to be atop the ticket in November.
"Let me make it very clear to you, Tony: I am not going to be a candidate for president, I am a candidate for basically speaking for the middle of this country," Manchin said on "CBS This Morning."
"I am not running for office, I could not believe that there was not going to be a primary process or a mini process. I don't need that as far as in my life, the attention that people think 'oh, when you speak up you're looking for attention.' Why is everybody afraid to speak up?" Manchin said.
Instead, Manchin said he was advocating for a "process" for selecting a "new generation" of leadership.
"I think a lot of people would like to see a mini primary -- that's the process," he said.
-ABC News' Allison Pecorin
