Nine people were killed and at least 26 others injured Sunday morning when a charter bus slid off an icy stretch of Interstate 84 in northeast Oregon, smashed through a guardrail and plunged about 200 feet down a steep embankment, Oregon State Police said.

Troopers said the driver of the westbound bus lost control around 10:30 a.m. on the snow- and ice-covered lanes about 13 miles east of Pendleton. The bus crashed through a guardrail and went down an embankment a few hundred feet, troopers said.

The bus came to rest at the bottom of a snowy slope and landed upright, with little or no debris visible around the crash site.

More than a dozen rescue workers descended the hill and used ropes to help retrieve people from the wreckage in freezing weather.

Troopers said the bus reportedly was on a return trip from Las Vegas to Vancouver, B.C. They later identified the charter bus company as Mi Joo Tour & Travel of Vancouver, B.C.

A woman who answered the phone at a listing for the company confirmed with The Associated Press that it owned the bus and said it was on a tour of the Western U.S. She declined to give her name.

A bus safety website run by the U.S. Department of Transportation said Mi Joo Tour & Travel has six buses, none of which have been involved in any accidents in at least the past two years.

Investigators were still on the scene as night fell, but all of the bus occupants had been removed.

OSP and other agencies were working to confirm the total number of passengers, initially reported at about 40.

St. Anthony Hospital in Pendleton confirmed 26 patients were brought there, five of which were flown to another hospital for treatment; the other 21 remained at the Pendleton hospital.

The bus driver survived the crash, troopers said, but investigators had been unable to speak to the driver due to the severity of the injuries.

Troopers said the names of those aboard also won't be released immediately. Release of the victims' names could be delayed further because they came from Canada, they added.

The cause of the crash was not known, troopers said, as investigators remained on scene doing their initial investigation.

Rescue workers used ropes to help retrieve people from the crash scene, up onto the highway.

The East Oregonian said it spoke with two South Korean passengers, ages 16 and 17. Both said through a translator that they were seated near the rear of the bus when it swerved a few times, hit the guardrail and flipped. They described breaking glass and seeing passengers pinned by their seats as the bus slid down the hill. Both said that they feared for their lives.

The paper said that the teens, one of whom injured a knee and the other suffered a broken collarbone, were staying at a hotel arranged by the Red Cross.

The Umatilla County Office of Emergency Management opened up the Convention Center in Pendleton for any bus occupants who were not hospitalized. The Red Cross will be helping at that location, troopers said Sunday night.

A tentative list of agencies involved at the scene:

* Umatilla Tribal Fire Department

* Pendleton Fire & Ambulance Service

* Pilot Rock Rural Fire Protection District

* East Umatilla Health District

* Milton-Freewater Rural Fire Department

* Walla Walla Fire Department

* Union County Ambulance