A search is on for the gunmen who killed four and injured six others in a "targeted" mass shooting in a Fresno, California, backyard Sunday night, authorities said.
About 30 people were at the Fresno home for a "quiet" and "peaceful" family party to watch football before it turned into a "mass casualty event," Fresno Police Chief Andrew Hall said at a news conference Monday.
Just before 8 p.m. local time, at least two suspects, both armed with pistols, walked into the backyard "and began immediately firing into the crowd," Hall said.
About 16 men were in the backyard at the time, he said, and 10 of those 16 men were struck by bullets.
The CEO of the Fresno Center, Pao Yang, said two of the victims who died were well-known singers in the Hmong community.
"They come out and perform... especially gearing up for Hmong New Year," Yang said. "Our community is in mourning."
The four people killed were all men, ages 23, 31, 38 and 40 years old, according to the chief.
The suspects never entered the home, where the rest of the partygoers were, according to police. Witnesses described only seeing flashes of light from the gun, the chief said.
Children were inside the home but none of them were hurt, authorities said. The house was not struck.
The unknown suspects fled on foot, said Hall.
He described the mass shooting as a "targeted act of violence against this residence" and said some people at this home may have been involved in a disturbance earlier this week. While the attack seemed targeted, the gunmen appeared to fire at random, Hall said.
There is no indication that anyone at the home was affiliated with a gang, Hall said, adding, "at this point we have not ruled gang involvement out."
Authorities are "investigating several leads" and the Fresno Police Department is forming an Asian gang task force, according to Hall. Fresno Police Capt. Anthony Martinez said the shooting was in a district with a lot Hispanic families and Southeast Asian families, especially those from the Hmong community.
"That entire neighborhood was victimized when this took place," Martinez said.
Fresno Mayor Lee Brand said in a statement, "Those responsible for this horrific crime will face the full force of justice. The City of Fresno will not tolerate this type of violence in any of our neighborhoods."
Two of the injured victims remain in the hospital and are in stable condition, Hall noted.
ABC News' Marilyn Heck and Alex Stone contributed to this report.