A man suspected of killing 10 people in a Chinese New Year mass shooting in California died of a self-inflicted gunshot wound in his van as officers closed in.
Los Angeles County Sheriff Robert Luna said the man was found dead in the vehicle he used to flee the scene of an attempted second shooting.
The suspected gunman was identified as 72-year-old Huu Can Tran.
Mr Luna said no other suspects were still at large.
Earlier on Sunday police surrounded the van with tactical vehicles and bomb squad trucks.
Mr Luna said the shooting at the Star Ballroom Dance Studio in Monterey Park, Los Angeles, left five women and five men dead, with another 10 people wounded.
The gunshots were mistaken by some for New Year fireworks, according to Tiffany Chiu, 30, who was celebrating at her
parents' home near the ballroom.
"A lot of older people live here, it's usually really quiet," she told Reuters news agency. "This is not something you expect here."
Then, 20 to 30 minutes after the first attack, a man with a gun entered the Lai Lai Ballroom in nearby Alhambra, and people wrested the weapon away from him before he fled, Mr Luna said.
The authorities believe the two events are connected but have offered no details about a motive.
The shooting has sent a wave of fear through Asian American communities in the Los Angeles area and cast a shadow over Lunar New Year festivities around the country. Other cities sent extra officers to watch over the celebrations.
The massacre was the nation's fifth mass killing this month.
Monterey Park is a city of about 60,000 people on the eastern edge of Los Angeles and is composed mostly of Asian immigrants from China or first-generation Asian Americans.
The shooting happened in the heart of the city centre where red lanterns decorated the streets for the Lunar New Year festivities. A police car was parked near a large banner that read "Happy Year of the Rabbit!"
The celebration in Monterey Park is one of California's largest and had attracted tens of thousands of people throughout the day.
Two days of festivities, which have been attended by as many as 100,000 people in past years, were planned, however officials cancelled Sunday's events following the shooting.
President Joe Biden condemned the killings in a written statement and said he had directed his homeland security adviser Elizabeth Sherwood-Randall to mobilise federal support to local authorities.
"As we await more crucial information from law enforcement, I want to assure the community of Monterey Park and the broader area that we will support you in every way we can," Mr Biden said.