Updated

Two people were killed and 33 injured Sunday when a bus crashed on an icy Montana road.

The bus departed from Billings, Mont., with 35 people on board and crashed near Clinton, about 330 miles away, at around 7:30am local time, the Missoulian reported.

Emergency responders reportedly had difficulty reaching the bus after the accident due to the treacherous conditions on Interstate 90.

Several passengers were ejected when the bus slid on black ice, rolled over and landed on its side in the highway median, Montana Highway Patrol Capt. Greg Watson said. No other vehicles were involved.

Two of the injured were listed in critical condition and eight others were in serious condition, according to another highway patrol officer. The other victims were hospitalized with various injuries.

The identities of the two victims who were killed were not released.

The driver of the bus was one of the survivors of the crash. American Bus Association spokesman Dan Ronan said he "has a good safety record" and "is a solid driver, with no issues of reliability."

The 53-year-old driver told Rimrock Stages, which operates the bus, that he was going 65mph at the time of the accident in a 75mph zone, according to Ronan.

"Company officials are extremely distraught about what happened," he said. "This is the first fatal accident that Rimrock has had in 27 years."

The Montana Highway Patrol is investigating the cause of the crash.

Several other accidents were reported Sunday morning on the same stretch of Interstate 90, according to the Missoulian.