The Saskatchewan Health Authority said multiple patients were being treated at several sites.
“A call for additional staff was issued to respond to the influx of casualties,” authority spokeswoman Anne Linemann said in an email.
Mark Oddan, a spokesman with STARS Air Ambulance, said two helicopters were dispatched from Saskatoon, Saskatchewan and another from Regina.
He said two carried patients to the Royal University Hospital in Saskatoon, while the third carried a patient to Royal University from a hospital in Melfort, a short distance southeast of Weldon.
Mr Oddan said that due to privacy laws, he could not disclose information about their ages, genders or conditions.
The stabbings were among the deadliest mass killings in modern Canadian history and certain to reverberate throughout the country, which is unaccustomed to bouts of mass violence more commonly seen in the United States.
“The attacks in Saskatchewan today are horrific and heartbreaking. I’m thinking of those who have lost a loved one and of those who were injured,” Canadian Prime Minister Justin Trudeau said in a message posted on Twitter.