Image copyright Highlines School District Image caption Kenney Bui died after being tackled during an American football game

A Seattle teenager has died of injuries that he suffered while playing for his school's American football team.

Kenney Bui, 17, suffered internal bleeding during a game on Friday night and spent the weekend in hospital.

Susan Enfield, the head of the school district, called the event "a devastating loss" on Monday.

Bui is the fourth US high school football player to die in the last month, raising questions about the safety of the sport.

Catherine Carbone Rogers, a spokeswoman for the school district, said that coaches are trained to recognise and cope with medical emergencies including concussions.

"All of our coaches are certified in concussion recognition and prevention, CPR and sudden cardiac arrest," she said.

The teenager had just started his final year at Technology and Communications High School in Seattle, Washington.

He was tackled in the fourth quarter of the game and taken by ambulance to hospital. The remainder of the game was cancelled.

Image copyright Family photos Image caption High school students Tyrell Cameron (left), Ben Hamm and Evan Murray died after being injured playing American football

The school placed a tribute on its website, notifying the community about the tragic events.

"Our deepest condolences go out to Kenney's family and all who knew him," the site read.

In the last month, three other US high school students have died of injuries suffered during American football games - Tyrell Cameron in Louisiana, Ben Hamm in Oklahoma and Evan Murray in New Jersey.

Deaths and serious injuries have continued despite attempts to improve helmet safety at all levels of the sport over the last few years.

Concerns about players' safety and the long-term effect of head trauma sustained while playing have been raised in the professional league as well.