At least eight people were killed in shootings at three different spas in the US state of Georgia.
Police said four people were killed at a massage parlour in Acworth, a suburb north of Atlanta, and four more at two spas in the city itself.
South Korea later confirmed that four of the victims were of Korean descent.
Officials said a 21-year-old man had been arrested and was believed to be the suspect in all three attacks.
A motive is yet to be established.
Sheriff’s office spokesman Captain Jay Baker said investigators were “very confident” that the same suspect was the gunman in all three shootings.
Authorities say it is too early in the investigation to know if the victims were targeted because of their race or ethnicity.
Hate crimes against Asian-Americans have spiked in recent months, fuelled by rhetoric that blames Asian people for the spread of Covid-19.
In an address last week, President Joe Biden condemned “vicious hate crimes against Asian-Americans who have been attacked, harassed, blamed and scapegoated.”
The first shooting happened at Youngs Asian Massage Parlor in Acworth, Cherokee County.
Captain Jay Baker said two people died at the scene and three were taken to hospital, where two more died. He later confirmed that the victims were two Asian women, a white woman and a white man, and that a Hispanic man had been wounded.
Less than an hour later, police were called to a “robbery in progress” at Gold Spa in north-east Atlanta.
“Upon arrival, officers located three females deceased inside the location from apparent gunshot wounds,” police said in a statement.
While there, officers were called to a spa across the street, called Aromatherapy Spa, where they found another woman shot dead.
Police quoted by the Atlanta Journal-Constitution said that all four Atlanta victims were Asian women.
Investigators who had studied CCTV footage then released images of a suspect near one of the spas. Police said that, after a manhunt, Robert Aaron Long, of Woodstock, Georgia, was arrested in Crisp County, about 150 miles south of Atlanta.