Police on Sunday warned tourists in London to beware of people pretending to be plain-clothes officers and stealing credit cards and cash during the Olympics, and said they arrested more touts for illegally reselling Games tickets.
The capital's Metropolitan Police Service said it arrested three men aged between 27 and 35 years on Saturday on charges of impersonating a police officer and conspiracy to steal.
"There have been a number of incidents where criminals have impersonated police officers to take money off unsuspecting tourists," said Detective Superintendent Steve Osborn.
"Officers would never take money from you, they would never take you to a cashpoint and ask you for money. They are unlikely to ask to see your bank cards and would never need to ask you for your pin number," he added.
Saturday's arrests were made in central London's Russell Square, where London 2012 organisers are running a transport service for media covering the Games.
Police said there was no direct connection between the arrests and the Olympics, but noted such con-men could be attracted to London by the lure of extra tourists during the Games.
The London force also said it had arrested another three people for illegally reselling Olympic tickets, known as touting in Britain and scalping in the United States, after nabbing 16 on Friday and Saturday.
Two of those held on Sunday were arrested outside Horse Guards Parade in central London, site of the beach volleyball tournament.
Three more people have been charged with various offences in connection with a mass alternative cycle ride that officers stopped near the Olympic stadium in east London on Friday evening, the police said.
Officers arrested 182 cyclists taking part in the "Critical Mass" ride for ignoring an order to stay away from the Olympic Park while the opening ceremony was underway.
All but four of those arrested have been released on bail pending further inquiries.