Six people were killed and 12 others suffered “varying degrees of injuries” in a mass shooting in an area of downtown Sacramento, California bustling with nightlife, police said.

Investigators believe multiple shooters opened fire just steps from the Capitol, in the wake of a large fight, after last call early Sunday.

“We know that a large fight took place just prior to the shootings, and we have confirmed that there are multiple shooters,” Sacramento Police Chief Kathy Lester said at an afternoon press conference.

The dead include three men and three women, Lester said.

One of the deceased was identified by his family to NBC News as Sergio Harris. He was 38, according to The Associated Press.

His sister, Kay Harris, 32, told the news agency that she had been asleep when a family member called her to say they feared her brother had been killed.

Lester said gunfire had been heard by officers near the scene at around 2 a.m. The officers rushed to the scene, administered CPR and secured the scene, the chief said.

At least one city security video camera captured some of the violence, the chief said, and investigators noted that some area buildings were struck by gunfire.

“The scale of violence that just happened in our city is unprecedented in my 27 years at the Sacramento Police Department,” Lester said.

The injured were being treated at area hospitals. Lester said her detectives would get to the bottom of the attack and hold those who opened fire accountable.

President Joe Biden called on Congress for further action to address gun violence in the wake of the incident.

“Today, America once again mourns for another community devastated by gun violence,” he said in a statement Sunday. “But we must do more than mourn; we must act.”

Mayor Darrell Steinberg called the shooting “a senseless and unacceptable tragedy.”

“Can we not have a sane debate where, on one side of the line, you say that people who want to use firearms for sport or for hunting or, you know, with reasonable self-defense on one side of the line, and on the other side of the line we say there is absolutely no place for rapid-fire assault weapons anywhere, anyhow?” Steinberg asked. “I mean, can we have that? Can we make that distinction?”

City Council member Katie Valenzuela, through tears, said she was “heartbroken” and “outraged.”

“Our community deserves better than this. This is not unique to Sacramento, but we can stop it here,” Valenzuela said.

“Enough is enough. And I will travel wherever I need to travel and I will talk to whoever I need to talk to get these guns off our streets and to give our youth what they need so that they can be successful and that they don’t get shot down on K Street when they’re out trying to have a good time,” she said.

Police said that about 9 a.m. local time they were aware of a social media video that might show an altercation before the shooting. The department asked for those who were at the scene to share any related video they might have.

Video posted on Twitter showed people running through the street as rapid gunfire could be heard in the background.

Video also showed that multiple ambulances responded. The shooting happened steps from City Hall, in an area that is packed with bars, restaurants, hotels and museums.

Berry Accius, a community activist, said he witnessed chaos when he went to the scene shortly after the shooting.

“The first thing I saw was, like, victims. I saw a young girl with a whole bunch of blood in her body, a girl taking off glass from her, a young girl screaming, saying, ‘They killed my sister.’ A mother running up, ‘Where’s my son? Has my son been shot?'” he said.

London Sacramento, a nightclub a block from the shooting, said in a statement that “each night, London Sacramento enforces strict security protocols and begins closing procedures at 1:30 a.m.”

“Our prayers are with the affected families and we continue to grieve with the Sacramento community,” the statement said.

City Hall was serving as an information center for victims’ families, police said Sunday morning.

Steinberg wrote in a statement on Twitter: “Words can’t express my shock & sadness this morning. The numbers of dead and wounded are difficult to comprehend.

“Rising gun violence is the scourge of our city, state and nation, and I support all actions to reduce it,” he added.

Gov. Gavin Newsom also released a statement, saying: “Sadly, we once again mourn the lives lost and for those injured in yet another horrendous act of gun violence.

“As it is early in this investigation, my Administration will continue to work closely with local and state law enforcement as we monitor the situation,” he said. “What we do know at this point is that another mass casualty shooting has occurred, leaving families with lost loved ones, multiple individuals injured and a community in grief.”