A teenage student was killed and eight others injured after two pupils opened fire in a US school on Tuesday.
Both attackers at the STEM School Highlands Ranch, near Denver, Colorado have been arrested, the police said.
Highlands Ranch is just 8km (5 miles) from Columbine High School – the site of one of the US’s worst school shootings 20 years ago.
This is believed to be the 115th mass shooting in the US in 2019.
Just before 14:00 local time (21:00 Nigerian time) the attackers “walked into the STEM school, got deep inside the school and engaged students in two separate locations”, Douglas County Sheriff Tony Spurlock said.
One suspect was a male youth, while the other was an adult man. Both were pupils at the school.
Officers were on the scene about two minutes after receiving the call, the sheriff’s office said
Mr Spurlock said the school contacted the emergency services “almost immediately”, and that officers arrived at the scene about two minutes later.
The school was closed and placed on lockdown as police attended the scene. It was eventually lifted an hour later, at about 15:00 local time.
One 18-year-old male pupil was fatally shot. A handgun was later recovered at the scene.
“We have no information about anyone being targeted,” Mr Spurlock said, adding that it was too early to come to any conclusions.
One parent, named in local media as Fernando Montoya, said his 17-year-old son was shot three times and wounded.
“He said a guy pulled a pistol out of a guitar case and started to shoot,” Mr Montoya told ABC affiliate Denver 7.
Colorado Governor Jared Polis tweeted he would send extra police officers to the scene.
The White House also tweeted its condolences to the victims, while spokesman Judd Deere said President Donald Trump “has been briefed and continues to monitor the ongoing situation”.