Almost half of the passengers taken to hospitals after a tour bus flipped over on a British Columbia highway have been released, health officials said Saturday.

The news provides some relief after all 56 people on board the bus were injured while it was returning from a tour of the Rocky Mountains. The passengers were tourists from Canada, mainland China, Hong Kong, Taiwan and the United States.

Fraser and Interior health authorities said 26 of the 55 people taken to hospital have been discharged.

Interior Health said three people are in critical condition, and two more are being treated for serious injuries — a significant decrease from the last update.

On Friday, Interior Health said seven people were listed in critical condition, six others were being treated for serious injuries, and 11 remained in hospital with other less severe injuries.

RCMP said in a news release some children were on board, but none suffered serious injuries when the bus crashed about a three-hour drive away from Vancouver.

Coquihalla Super Vacation tour bus crash - Aug. 28, 2014

A Super Vacation tour bus carrying 56 people hit a median on Thursday afternoon about 30 kilometres south of Merritt, B.C., then skidded across several lanes and rolled into a ditch, ejecting numerous passengers. (CBC)

Once the accident happened, authorities initiated a code orange response, which means hospital workers should get ready for mass casualties.

Darshan Lindsay, spokeswoman for Interior Health, said things appear to be going back to normal at Interior hospitals, which were were filled with extra staff who were scrambling to keep up with the influx of patients at the time of the accident.

"Since then, as patients have been treated, things have definitely normalized," she said. "We've seen many discharges as well."

"We have seen some patients move from the serious condition to non-life-threatening condition because they have seen some improvement."

Tour operator trying to help

The vehicle was carrying a tour group organized by Super Vacation, a company based in Richmond, B.C., which describes itself as the largest Chinese tour operator in North America.

Nicholas Kam, Super Vacation director of sales - Aug. 29, 2014

Nicholas Kam, left, director of sales at Super Vacation tells reporters his company is trying its best to help the tourists injured in the Thursday's crash on the Coquihalla. He said the bus involved was operated by Western Bus Lines. (CBC)

The company has said it has been in contact with some of the passengers and was trying to figure out ways to help.

Super Vacation has said the bus was operated by Western Bus Lines, which describes itself as a company with 35 years of experience in providing safe, reliable and affordable transportation.

On Friday, a person who answered the phone at the Western Bus Lines office said the company had no comment, then hung up.

Further requests for comment were not immediately returned.

Investigators have yet to determine the cause of the accident, but have ruled out speed and road conditions after RCMP viewed video footage of the crash.

Police have said mechanical inspections are underway and will allow them to determine if faulty steering or braking was responsible for the accident.

A phone line has been established by the Red Cross to direct family members of victims to the hospitals where they are staying.

With files from CBC News