Democratic hopefuls have weighed in on the Friday shooting in Virginia Beach that left 12 dead and four injured as of Saturday afternoon, mourning the lives lost and calling for an end to such shootings.

Joe Biden

The former vice president tweeted Friday, "11 innocent lives cut down. 11 more futures denied. When will we finally say enough is enough? It’s long past time to hold our leaders accountable. Jill and I are heartbroken that more American families are suffering tonight in Virginia Beach."

Cory Booker

Booker addressed the shooting at the top of his remarks Saturday at the MoveOn Forum in San Francisco, California.

"We had another mass shooting in America yesterday, and these cannot just go on in our country," the New Jersey senator said. "We used to be a nation that when four girls were killed in a bombing in Birmingham, we changed laws. When women were killed in the Shirtwaist Factory fire, we changed laws."

"We are seeing too much death in our country," he said, adding later that it reminded him that "the power of the people is greater than the people in power, and when the people are united, they cannot be defeated."

Steve Bullock

"Too many lives cut short. This has to stop. I’m holding Virginia Beach in my heart tonight," the Montana governor tweeted.

Pete Buttigieg

Speaking at the Service Employees International Union Breakfast in San Francisco, the South Bend, Indiana, mayor told reporters, "We cannot tolerate being the only developed nation where this is routine. We know it’s not the last time this is going to happen and Washington’s failure to act is costing lives."

Julián Castro

"Heartbreaking news out of Virginia Beach as another community copes with a senseless gun violence attack," the former Housing and Urban Development secretary tweeted Friday. "We can and must pass common sense reforms to end the gun violence epidemic—and ensure no community has to endure the pain that the Virginia Beach community feels today."

John Delaney

"Our hearts are with the people of Virginia Beach, especially the victims and their families in this time of grief," the former Maryland congressman tweeted, adding, "We can't accept this as normal, we need to take action on gun safety. We can't go on like this."

Kamala Harris

The California senator tweeted Friday, "Heartbroken for the victims and their families of the Virginia Beach shooting and grateful for the first responders on the scene. This senseless act of violence should not be normal. Too many communities have been shattered by gun violence — we cannot continue to stand idly by."

John Hickenlooper

"The news out of Virginia Beach is simply devastating," the Colorado governor tweeted. "Public servants who just showed up to do their job are not coming home tonight because of gun violence. This story has played out too many times in too many towns. We need to stand up and stop this. #EnoughIsEnough"

Jay Inslee

The Washington state governor also addressed the shooting outside the SEIU Breakfast Saturday, calling for action on national gun safety laws, similar to those in his home state, as soon as tomorrow.

"Look, this is a pain that’s felt all across America, not just Virginia and for those folks who said we should not talk about gun safety, in the wake of this tragedy, that’s just wrong," he told reporters. "This is exactly the time we need to talk about gun safety. And I’m hopeful that we can pass the laws in America that I’ve passed, that we’ve passed in Washington state. We need common sense gun safety. We need it now. Let’s get this started tomorrow."

Amy Klobuchar

Speaking outside the the SEIU Breakfast in San Francisco, the Minnesota senator lamented that "we’ve seen way too many of these" types of tragedies, adding that while her thoughts were with the victims' loved ones, "Enough is enough."

She slammed Senate Republicans and President Donald Trump for stalling gun safety reform, pointing to the House of Representatives passing universal background check legislation that is now "sitting at Mitch McConnell’s door," as well as the Violence Against Women Act "that is also stopped in the Senate because they’re so afraid of the NRA."

"I sat across from President Trump after Parkland while he was telling us, 'Oh yeah, let’s get universal background checks done. Let’s get all this stuff done,'" she said. "He never did it. He met with the NRA the next day and he turned on it, so it is time to get this done."

Wayne Messam

The Miramar, Florida, mayor tweeted, "My heart cries for the Virginia Beach victims lost and the survivors who must now make sense of this senseless act of gun violence. I’m committed to doing my part to help make this nation a place where these incidents never happen ever."

Beto O'Rourke

The former El Paso congressman weighed in on the shooting Saturday outside the SEIU Breakfast in San Francisco, calling the deadly violence "just horrifying."

"In the face of this, we as a country must change and ensure that we take action," he said, praising young activist calling for gun safety legislation.

"They’re going to force this change that we desperately need in this country, but (I'm) just incredibly saddened at the loss of life and the continuing tragedy that we’re seeing in this country," O'Rourke added.

Bernie Sanders

"What can you say, it’s a terrible tragedy," the Vermont senator told reporters Saturday at the SEIU Breakfast in San Francisco, before calling for gun safety legislation.

"It speaks to the need for this country finally to do what the American people want and that is common sense gun safety legislation and that is making sure that people who should not own guns, do not own guns, and doing everything we can to make this country and our schools safer," he added.

Eric Swalwell

The California congressman, who centered his campaign announcement on gun safety, tweeted, "As I was with a film crew recording a video on mass shootings we were told another community has suffered a mass shooting."

"#Virginia, we mourn with you. This can never be normal. It is never too early for us to also say #EnoughIsEnough," he added."

Elizabeth Warren

The Massachusetts senator addressed the shooting when asked about her plans on gun control during the MoveOn Forum Saturday, contextualizing it in what she called a larger "gun problem in America."

"We talk a lot about mass shootings and I’m very sorry about what happened yesterday in Virginia Beach," she said. "But it’s not just mass shootings. This is happening all across America, it's happening on sidewalks and playgrounds, in people’s backyards. It’s happening family by family across this country and it doesn’t get the same headlines, and that is wrong."

"We have a gun problem in America, and it is putting our children at risk all across this nation." she added.

Andrew Yang

"The shooting in Virginia Beach is a nightmare come to life - a disgruntled employee who massacred innocents," the businessman tweeted. "My heart goes out to the families and individuals who were killed and injured. We have to make it harder for people to get and use guns that can cause such tragedies."

CNN's Aishvarya Kavi, Ali Main, Annie Grayer, Alison Main, Rashard Rose, Jasmine Wright, Caroline Kenny, Leyla Santiago and Arlette Saenz contributed to this report.