Three men have been detained by police in connection with alleged fraudulent ticket sales at the Open.
A number of fake tickets have also been seized by officers.
The men, who are not from the area, are aged 34, 47 and 52.
Police said the people who had presented the tickets at the entrance gates were spoken to as witnesses, and then given the option to buy valid tickets.
Superintendent Phil O’Kane, who is leading the policing operation at the Open, said: “The championship is a major international sporting event and it is only to be anticipated that unscrupulous people will try to exploit it.
“However, due to the vigilance of the security staff and the police officers on the course, these fraudulent tickets were identified.
“Inquiries are ongoing into this fraudulent ticket activity.”
Police are reminding the public that tickets must be purchased from official outlets. Tickets that have not been sourced through either the R&A or Ticketmaster will not be accepted.
Supt O’Kane added: “It can prove to be a costly exercise to purchase a ticket from anything other than an official outlet and I would urge people not to pay above the ticket price… and, when they are leaving the course at the end of their visit, not to be tempted to resell their ticket – it will only be used to exploit another innocent individual.”