Police have shot and killed a man in the emergency unit of a hospital in Guelph, Ont.

"At approximately 1 p.m. today, Guelph Police Service members were involved in a critical incident. It occurred at the Guelph General Hospital in their emergency unit," said spokesman Const. Mike Gatto.

The officer said he couldn't give out any more information, noting the Special Investigations Unit, Ontario's police watchdog, is investigating.

Two officers discharged their firearms and the man was declared dead at the scene, the SIU said in a release.

A witness told CBC News that she saw a woman running out of the hospital while yelling, "My boyfriend's shooting at me."

"There's blood on the ground," the witness said. "It was freaky."

According to the hospital, the shooting occurred in the waiting room of the emergency department.

"Our [emergency department] remains open, although wait times will be longer than usual," said Marianne Walker, the hospital president and CEO, in a news release. "Our focus now is to provide support to all those who need it, including staff, patients and visitors."

Ten investigators, including four forensic specialists, are investigating the shooting.

The SIU is an arm's-length body that is called in to investigate cases in which a member of the public has sustained severe injuries or died in an interaction with police.