Three men have been ejected from the Diamond Games in Antwerp for illegally betting on tennis matches.
Officials said the trio were using wireless laptops to access gambling websites, betting on points before they had registered on the internet.
"We spoke with the WTA. They had the chance to give up their computers or to leave - they left," said an official.
The expulsions are the first cases in tennis's new anti-corruption policies to clamp down on illegal betting.
The three men - two Germans and a Russian - also had their photographs taken to prevent them from returning to the tournament, which finishes on Sunday.
The game's various governing bodies joined forces in January to review their anti-corruption commitments after recent match-fixing and betting scandals.
The International Tennis Federation, the ATP, the WTA and the organisers of the Grand Slams are all involved, along with two British police officers.
A match involving world number four Nikolay Davydenko is still being investigated by the ATP over irregular betting patterns.
And three Italian players, Potito Starace, Alsip Di Mauro and Daniele Bracciali, have all received bans for betting on other players' matches.