As the holiday shopping season starts, the Thunder Bay Police Service wants to remind citizens and businesses in northwestern Ontario to be extra careful when accepting or using U.S. currency.

On Sunday afternoon, officials said they responded to a complaint of a resident attempting to purchase goods from a business with a suspicious U.S. $20 bill.

Upon investigation, police said they not only confirmed that the bill was counterfeit but also discovered that similar fake bills of different denominations could be circulating in the city, as they have seized both $20 and $50 counterfeit bills.

Officials are asking the public to be extra diligent and to contact police if anyone sees a suspicious bill.