An elderly couple have been pronounced dead after suffering what is believed to be carbon monoxide poisoning at an Etobicoke home, Toronto paramedics say.

Police were called to the home on Bywood Drive in the Islington Avenue and Rathburn Road area just before 9:30 p.m.

That's where they say two victims were found unconscious and not breathing.

Toronto Fire Services Capt. Michael Westwood told CBC Toronto a high level of carbon monoxide was found at the home.

Paramedics say the pair were pronounced dead on scene and that carbon monoxide exposure is believed to be the cause.

The source of the gas is not yet known, and there are no other injures at surrounding homes, Westwood said.