A woman is dead and a man suffered serious injuries after being hit by a 16-seat Hainan Airlines tour bus west of Calgary on Wednesday. Both were tourists from Ontario, according to Alberta RCMP.

The tour bus stopped at the Castle lookout along the TransCanada Highway in Banff National Park before 10 a.m. MT. Police said the tourists got out to take photos at a scenic spot just above the Bow River.

A Hainan Airlines bus sits submerged in the Bow River near Banff, Alta. on Wednesday, Sept. 21, 2016 following an incident that killed one person and injured another. Global News / Mia Sosiak A Hainan Airlines bus sits submerged in the Bow River near Banff, Alta. on Wednesday, Sept. 21, 2016 following an incident that killed one person and injured another. Global News / Mia Sosiak RCMP respond to the Castle Mountain lookout near Banff, Alta. on Wednesday, Sept. 21, 2016 following an incident that killed one person and injured another. Global News / Mia Sosiak

RCMP said while the tourists were taking photos, the empty bus started rolling forward into the water. It struck two people who were standing in front of the bus. They were hit and thrown through a fence, down a steep embankment and landed on the ground near the river.

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“How the bus moved forward on its own is part of our investigation,” Banff RCMP Cpl. Chris Blandford told Global News. “At this time, we don’t know how it happened.

“I’ve been with the RCMP now for 28-and-a-half years…I’ve never seen anything like this. On the surface, it appears to be an unfortunate incident.” Tweet This

A 53-year-old woman died on scene. A 55-year-old man was airlifted to the Foothills Medical Centre in Calgary by STARS Air Ambulance, which was sent to the scene at 9:58 a.m.

WATCH: One Ontario tourist was killed and another injured after being struck by a tour bus close to Banff. The bus had stopped for the tourists to take pictures when it started to roll into a river valley, taking the two people with it. As Reid Fiest reports, the cause is still under investigation.

1:39 Deadly bus accident at Banff tourist stop Deadly bus accident at Banff tourist stop

Covenant Health said an ambulance was sent to the scene from Banff at about 9:52 a.m.

STAR-1 (Calgary) has been dispatched for a scene call emergency in the Banff, AB area. — STARS Ambulance (@STARSambulance) September 21, 2016

The bus was pulled from the Bow River Wednesday afternoon. Two tow trucks were called to pull it out of the river so police could continue the investigation.

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Hainan Airlines said it was “deeply saddened” by the bus accident and will work with authorities to support the investigation.

“The tour bus bearing the Hainan Airlines logo is owned and operated by another company, not Hainan Airlines,” reads a statement from the airline’s Calgary office. “At the time of the accident, the bus was not servicing Hainan customers or employees.”

In addition to the Chinese airline’s logo, text on the side of the bus said it was operated by Calgary company Amazing Travel Inc.

On Thursday, Amazing Travel issued a statement in response to the incident.

“Our thoughts and prayers go out to those affected by the incident,” the statement said in part. “This is a very difficult time for Amazing Travel and we ask that respect be given to the family and staff of the organization as they all deal with the grieving process. Counselors have been asked to be present for our staff.”

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The statement went on to say the company had “safely transported more than 20,000 clients throughout western Canada during its 10 years of operation” and that it was cooperating with authorities.

An employee who was with the group in Banff following the incident declined an interview, but said the buses have “never moved by themselves before.”

The tour group is continuing on to Jasper with a new driver and bus.

On Thursday, Alberta’s transportation ministry issued a statement in response to the incident.

“We are saddened to hear of this tragic incident,” the statement read in part. “Safety on our roads is a priority of our government.

“As standard practise, one of AT’s Public Safety Investigators will be assessing the regulatory compliance associated with this particular incident. They will also be conducting a full National Safety Code audit to measure the compliance of the company and verify that the company has management control of the compliance of all of their vehicles and drivers. This is also standard practise.”

Watch below: Banff RCMP Cpl. Chris Blandford updates the incident that saw one person killed and another injured after a tour bus rolled into the river.

2:41 RCMP on Banff tour bus incident RCMP on Banff tour bus incident

With files from Mia Sosiak and Reid Fiest

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