(CNN) -- Two people were killed and more than 30 others injured early Sunday when a charter bus crashed in icy conditions near Clinton, Montana, officials said.
The bus, operated by Rimrock Trailways, was en route to Missoula from Billings on Interstate 90 when it crashed, according to Dan Ronan of the American Bus Association. Black ice conditions were present on the highway, Ronan said.
"We are saddened by what happened and our condolences go out to the families," he said.
Two people were killed -- a 60-year-old woman from Illinois and a 56-year-old man from Montana, according to the coroner's office. Ronan previously put the death toll at three.
Thirty-four people were taken to local hospitals. At least two were admitted in critical condition, hospital officials at St. Patrick Hospital and Community Medical Center said.
Montana Highway Patrol Sgt. Scott Hoffman told CNN Billings affiliate KTVQ that several passengers were thrown from the bus and others were trapped underneath it.
The driver of the bus was among those injured, but his injuries were not life-threatening, Ronan said.