Three people have been killed and 15 injured after a gunman attacked a food festival in California.
The gunman was shot dead by police shortly after he began firing, although police are investigating reports that a second suspect may still be at large.
The Gilroy Garlic Festival was about to end for the weekend on Sunday evening, when shots were fired at the site.
Six-year-old Stephen Romero is the first of the dead to be identified. His mother and grandmother were wounded.
His father, Alberto Romero, told Mercury News that he was at home with his nine-year-old daughter when he got the panicked call from his wife.
They had been playing in an inflatable bounce house at the time of the attack, she told him, when the boy was shot in the back.
"I couldn't believe what was happening, that what she was saying was a lie, that maybe I was dreaming," said Mr Romero.
"He was joyful, always wanted to play, always positive," he said, adding that the boy's mother has been placed in a medically induced coma after being shot in the stomach and her mother was being treated for a gunshot wound in the leg.
It was the 246th mass shooting in the US this year, according to US tracking website Gun Violence Archive.
The killer has been identified as 19-year-old Santino William Legan, according to CBS News. Witnesses said he was wearing camouflage, and used a rifle during the attack.
Eyewitness Julissa Contreras told NBC that the attacker appeared to be "a white man in his early-30s".
The lead guitarist of the group TinMan, who was performing on stage when the attack began, said he heard someone ask the shooter: "Why are you doing this?"
Jack Vanbreen told the Associated Press that he heard the assailant respond: "Because I'm really angry".
Shooter 'cut the fence'
The suspect entered the festival after cutting through a perimeter fence, Gilroy Chief of Police Scot Smithee told reporters. He said witnesses reported that a second suspect may have been involved, possibly in a support role.
Officers were already at the site and responded to the shooting in less than a minute, Chief Smithee added.
Videos posted on social media showed people running away from the festival, which takes place 30 miles (48km) south of San Jose and attracts 100,000 people each year.
"What's going on?" a woman can be heard asking in one video, "who'd shoot up a garlic festival?"
"We couldn't feel worse," Brian Bowe, the festival's executive director, said at a news conference on Sunday. "It's just a horrible thing to experience."
"This is nothing short of horrific," tweeted California Governor Gavin Newsom.
US President Donald Trump on Monday thanked police "who swiftly killed the shooter".
He called the attacker "a wicked murderer" and vowed that the US would grieve for the families of victims and "ask that God comfort them".
Some people are being treated for critical injuries, a spokeswoman for the Santa Clara Valley Public Health System said.
The Santa Clara County Medical Center has so far admitted five victims, CBS reports. Two patients are being treated at a medical centre at Stanford University, according to CNN.
The hearts of Gilroy PD and entire community go out to the victims of today's shooting at the Garlic Festival. The scene is still active. If you are looking for a loved one, please go to the reunification center at Gavilan College at parking lot B. #GilroyActiveshooter— Gilroy Police (@GilroyPD) July 29, 2019
Michael Paz, 72, a hat vendor at the festival, told the San Francisco Chronicle that he saw a gunman armed with a rapid-fire assault rifle.
"He came ready to shoot because he was wearing a protective vest," Mr Paz said. "He was shooting left; he was shooting right without any particular aim."
As police swooped on the gunman and shots were fired, festival attendees dropped to the ground, Mr Paz said.
"It was just rapid firing," Ms Contreras told NBC Bay Area. "I could see him shooting in just every direction. He wasn't aiming at anyone specifically.
"It was just left to right, right to left. He definitely was prepared for what he was doing."
Evenny Reyes, 13, was among those who scattered in confusion when gunfire erupted at around 17:30 local time (00:30 GMT Monday).
"We were just leaving and we saw a guy with a bandana wrapped around his leg because he got shot," she told the San Jose Mercury News.
The Gilroy Garlic Festival has been held annually since 1979. The city is a major garlic producer and the event features cooking competitions and live entertainment.
Christmas Hill Park, where the event was taking place, bans weapons of any kind, according to the festival's website.
Gun Violence Archive defines a mass shooting as a gun attack in which at least four people are either killed or wounded.
In total, it estimates that 8,434 people have died as a result of gun violence in the US in 2019 so far.