DENVER (CBS4) – The Denver Broncos and the Denver Police Department are warning fans to beware of counterfeit tickets.

Police said the counterfeit tickets are making their way through secondary markets unaffiliated with the Broncos or the National Football League. The teams is urging fans to take appropriate measures to ensure the authenticity of their purchases.

Only tickets acquired from team-associated outlets, including the Sports Authority Field at Mile High ticket office and Ticketmaster/Ticket Exchange, can be fully validated by the club and the NFL.

“It’s important for fans to beware of the risks involved with purchasing tickets through websites and other vendors that are not certified by the NFL,” Broncos Senior Vice President of Business Development Mac Freeman said in a statement. “Those buying tickets through the ticket office, Ticketmaster or NFL Ticket Exchange can continue to be 100 percent assured that their tickets are authentic.”

Police are investigating recent incidents of ticket counterfeiting in the metro area.