Motive unclear in US dance club shooting

Authorities are yet to establish a motive after a gunman killed 10 people at a Los Angeles-area ballroom dance club during Lunar New Year celebrations, sending a wave of fear through Asian American communities and casting a shadow over festivities.

The suspect was found on Sunday, dead of a self-inflicted gunshot wound in a van in which authorities say he fled after people thwarted his attempt at a second shooting Saturday night.

The massacre was the nation's fifth mass killing this month.

It was also the deadliest attack since May 24, when 21 people were killed in an elementary school in Uvalde, Texas.

Los Angeles County Sheriff Robert Luna identified the man as 72-year-old Huu Can Tran and said no other suspects were at large.

Luna said the motive remained unclear for the attack, which wounded 10 people, seven of whom were still hospitalised.

Speaking at a Sunday evening news conference, the sheriff said he didn't have their exact ages but all of the people killed appeared to be aged more than 50.

The suspect was carrying what Luna described as a semi-automatic pistol with an extended magazine, with a second handgun discovered in the van where Tran died.

Monterey Park Police Chief Scott Wiese said on Sunday officers had arrived at the Star Ballroom Dance Studio in Monterey Park within three minutes of receiving the call.

There, they found carnage inside and people trying to flee through all the doors.

"When they came into the parking lot it was chaos," Wiese said.

About 20 to 30 minutes after the first attack, the gunman entered the Lai Lai Ballroom in the nearby city of Alhambra.

But people wrested the weapon away from him and witnesses said he fled in a white van, Sheriff Luna said.

The van was found in Torrance, another community home to many Asian Americans, about 34.5 kilometres from that second location.

After surrounding the vehicle for hours, law enforcement officials swarmed and entered it.

A person's body appeared to be slumped over the wheel and was later removed.

Members of a SWAT team looked through the van's contents before walking away.

The sheriff's department earlier released photos of an Asian man believed to be the suspect, apparently taken from a security camera.

Congresswoman Judy Chu said she still has questions about the attack but hopes residents now feel safe.

"The community was in fear thinking that they should not go to any events because there was an active shooter," Chu told Sunday's news conference.

"What was the motive for this shooter? Did he have a mental illness? Was he a domestic violence abuser? How did he get these guns and was it through legal means or not?"

Monterey Park, a city of about 60,000 people on the eastern edge of Los Angeles, is composed mostly of Asian immigrants from China or first-generation Asian Americans.

The shooting happened in the heart of its downtown where red lanterns decorated the streets for the Lunar New Year festivities - one of California's largest celebrations.

Two days of festivities, which have been attended by as many as 100,000 people in past years, were planned but officials cancelled Sunday's events following the shooting.

President Joe Biden and Attorney General Merrick Garland were briefed on the situation, aides said.

Biden said he and first lady Jill Biden were thinking of those killed and wounded and directed federal authorities to support the investigation.

A USA Today/Associated Press database on mass killings in the US shows 2022 was one of the nation's worst years with 42 such attacks - the second-highest number since the creation of the tracker in 2006.

The database defines a mass killing as four people killed, not including the perpetrator.