DOLAN SPRINGS, Ariz. -- The victims from an Arizona bus rollover have arrived at Las Vegas hospitals as officials confirm that seven people have been killed.

Arizona State Police received the call about the incident at mile marker 27 on Interstate 93 just after 3 p.m. Friday.

Six helicopters and four ambulances were requested to treat the 17 injured, with all of victims being routed to University Medical Center, Arizona police said.

The bus was headed to Las Vegas from the sky walk at the Grand Canyon when the wreck occured.

According to an employee at Rosie's Den -- a restaurant near the crash scene -- there were people trapped under the 24- to 28-foot bus.

Six people died. Authorities are still trying to determine what caused the wreck.

Four of the helicopters being sent to Las Vegas have landed at UMC. Hospital officials have confirmed that they have four victims and that one of them has died.

FOX5 has a crew en route. Watch FOX5 News at 10 and 11 and stay with fox5vegas.com for continual coverage of this story.