Three students have been killed and eight people wounded after a 15-year-old opened fire at his Michigan high school.
The attack happened at Oxford High School in Oxford Township, a community of about 22,000 people 30 miles (48km) north of Detroit.
The 15-year-old is in custody after being arrested at the school. Officers also recovered a semi-automatic handgun and ammunition.
Those killed were a 16-year-old boy, a 17-year-old girl and a 14-year-old girl.
The gunman’s motive remains unclear, said Oakland County Undersheriff Mike McCabe.
Officers responded at around 12:55pm local time to a flood of 911 calls about an active shooter.
The suspect was believed to have acted alone and was arrested without resistance after firing 15 to 20 shots.
More on Michigan
Michigan: Dad ‘saved daughter’s life’ by hugging her during plane crash – and she was the only survivor
Michigan: Girl, 11, only reported survivor of US plane crash that killed pilot and three passengers
Father sues school for $1m after teacher cuts daughter’s hair without permission
“The whole thing lasted five minutes,” Mr McCabe said.
Authorities did not immediately release the names of the suspect or victims but confirmed one of those injured was a teacher.
Tim Throne, the superintendent of Oxford Community Schools, said: “I’m shocked. It’s devastating.”
The school was placed on lockdown after the attack, with some children sheltering in locked classrooms while officers searched the premises.
They were later taken to a nearby shop to be picked up by their parents.
Michigan Governor Gretchen Whitmer called the shooting “horrific.”
“As Michiganders, we have a responsibility to do everything we can to protect each other from gun violence,” she said.