BRAMPTON, Ont. - The Region of Peel in Ontario is apologizing after it "accidentally" mailed letters to 16 residents saying their COVID-19 test results were negative when, in fact, they were positive.

Dr. Lawrence Loh, interim medical officer of health, says the letters were mailed on Tuesday and Wednesday.

He says his team is working quickly to notify these people and make sure they have what they need to manage this difficult situation.

Loh says an investigation found that several positive test slips were mixed with a batch of negative results received from labs.

He says the error was not noticed until after the notification letters were mailed.

Loh says they have made changes to their process to ensure that this does not happen again.