Three students have been killed and eight others injured, including a teacher, in a high school shooting in the US state of Michigan.
Officials say a 16-year-old boy and two girls aged 14 and 17 died.
Police allege the suspect, a pupil at the school, used a handgun that his father had bought on Friday.
Students have described hiding under desks during the attack. Some had stayed home on Tuesday because of safety concerns.
Police received emergency calls from the high school in the town of Oxford, about 40 miles (65km) from Detroit, at 12:51 local time (17:51GMT).
Within minutes, officials had received 100 calls to 911, Oakland County Undersheriff Mike McCabe told reporters.
Officials say the suspect, a 15-year-old boy, surrendered five minutes after police were called.
No shots were fired during the arrest, and the teenager was not injured, Mr McCabe said, adding later that the boy had been in class before the shooting began.
Oakland County Sheriff, Mike Bouchard, said his officers took down the shooter while he still had seven rounds of ammunition in the semi-automatic handgun.
He added that the male victim died in a local deputy's car before the officer could get him to the hospital.
The school was evacuated, and officials conducted three separate sweeps of the campus to ensure that there were no additional victims.
Two of the injured were undergoing surgery, while the other six were in a stable condition with gunshot wounds. Those injured range in age from 14 to 17 years old, according to the Associated Press. A teacher whose shoulder had a graze wound had been discharged from hospital.
In the news conference, officials said a motive for the shooting had not yet been determined, and that the suspect was not co-operating with authorities.
"The person that's got the most insight and the motive is not talking," Sheriff Bouchard told reporters.
Mr McCabe said that the boy had been told by his parents not to talk to police and that officers were searching his home.
All schools will be closed for the rest of the week and crisis support is being offered to students and parents.
"Of course I'm shocked. I'm devastated," said Oxford Superintendent of Schools Tim Throne.
Students stayed home because of safety concerns
According to the Detroit Free Press newspaper, rumours had been circulating of a possible attack, and some students had decided not to attend classes on Tuesday.
Parent Jody Job told the paper that her son had skipped school because "he felt like something was going to go down".
Robin Redding told the Associated Press that her son had also missed classes due to concerns about safety.
"He was not in school today," she said. "He just said that 'Ma I don't feel comfortable. None of the kids that we go to school with are going today.'"
Mr McCabe has cautioned against speculating on the safety concerns before the investigation is complete.
President Joe Biden spoke about the shooting during a visit to Minneapolis, Minnesota.
"My heart goes out to the families enduring the unimaginable grief of losing a loved one," he said.
US shootings on school grounds have been ticking steadily upwards in recent years, according to pro-gun control group Everytown.
After a brief dip last year during coronavirus lockdowns, the number of such attacks has rebounded with 138 incidents of gunfire on school grounds so far in 2021.
BDST: 1247 HRS, Dec 01, 2021