As reported by the Xinhua News Agency, the bus carrying 35 Chinese people from the United States, crashed on the 401 highway of Ontario causing the casualties.
"My understanding is they are tourists, there was a tour guide with them", Runciman said, adding that the passengers on board are from China.
Aiden Liang, the owner of the Union Tour Express bus company, said the bus left from Ottawa on Monday and was bound for Toronto.
Runciman said four of the 24 patients sent to hospital were believed to have life-threatening injuries.
The bus was sitting in the ditch, up against some rocks, he said.
Joshua McNamara, a spokesman for Ontario's air ambulance service, said that it flew three people farther west to Kingston.
He said the hospital set up a triage centre in a garage beside the emergency department.
Shawn O'Neil, operations manager at the Prescott Ambulance Station, said there are about 27 patients from the tour bus crash.
Four women and one man were admitted in critical condition to Brockville General Hospital, spokeswoman Abby McIntyre told Reuters. "What I've been advised is that we have received five of the most critical".
Eight other people were treated at a small hospital in Kemptville, and all were in stable condition, officials said.