At least 20 people were shot, 10 fatally, near a Lunar New Year celebration in the Los Angeles suburb of Monterey Park when a gunman opened fire inside a crowded dance studio, authorities said.
The gunman has not been identified and remains at large Sunday morning, said Capt. Andrew Meyer, of the Los Angeles County Sheriff's Department Homicide Bureau, which is leading the investigation.
Meyer said some of the injured were in critical condition, while others were reported as stable, he said.
Monterey Park had been hosting the Monterey Park Lunar New Year Festival this weekend, marking the beginning of the Chinese lunar calendar.
President Joe Biden has been briefed on the shooting, according to the White House, and the FBI has joined the investigation.
"The President has been briefed by the Homeland Security Advisor on the mass shooting in Monterey Park. He directed her to make sure that the FBI is providing full support to local authorities, and to update him regularly today as more details are known," the White House press secretary tweeted.
In early alerts sent to Washington, investigators said "they had no idea who the suspect was," Pierre Thomas, ABC News' chief justice correspondent, said on ABC's "This Week."
U.S. Attorney General Merrick Garland has also been briefed on the shooting, according to a statement from the Department of Justice.
Monterey Park had been hosting the Monterey Park Lunar New Year Festival this weekend, marking the beginning of the Chinese lunar calendar. The annual two-day street festival is widely attended, with previous celebrations drawing as many as 100,000 daily visitors, according to the city. More than 65% of Monterey Park's about 60,000 residents identify as Asian American, according to the U.S. Census Bureau.
In a statement Sunday morning, the city of Monterey Park clarified that the shooting did not occur at the Lunar New Year Festival but at the dance studio near the festival that was not connected to the festivities. Officials said Saturday's festival events were scheduled to finish at 9 p.m.
City officials said all festival activities for Sunday have been cancelled.
"Even though the incident did not occur at the 2023 Lunar New Year Festival, an active investigation is currently underway and the area near and around the festival is affected. As a precaution and for the safety of everyone, the City regrets to announce the cancellation of the second day of the festival," city officials said in a statement.
The Sheriff's Department said the shooting erupted around 10:22 p.m. on West Garvey Avenue, near the downtown blocks where the festival was being held.
The gunman opened fire shortly after entering a dance hall, where people had been celebrating the holiday, police said. It was unclear what type of weapon he used, police said.
Police officers who initially arrived at the scene, described a chaotic situation with panicked people running out of the dance hall.
Police in the nearby city of Alhambra were investigating an incident that might be connected to the shooting, officials said. The incident in Alhambra also occurred at a dance studio, according to ABC Los Angeles station KABC.
"To have this tragedy occur on Lunar New Year weekend, makes this especially painful," Alhambra Mayor Sasha Renée Pérez said in a Twitter post Sunday. "Monterey Park is home to one of the largest #AAPI communities in the country. This is a time when residents should be celebrating with family, friends and loved ones - not fearing gun violence."
The L.A. County Sheriff's Department said it would lead the investigation, after earlier saying it would assist Monterey Park Police. The FBI said it had responded to the scene to assist.
California Gov. Gavin Newsom released a statement on Twitter condemning the attack.
"Monterey Park should have had a night of joyful celebration of the Lunar New Year. Instead, they were the victims of a horrific and heartless act of gun violence," Newsom tweeted. "Our hearts mourn as we learn more about the devastating acts of last night. We are monitoring the situation closely."
This is a developing story. Please check back for updates. ABC News' Vanessa Navarrete contributed to this report.