In a sign that world soccer's governing body will not allow drug cheats to spoil the World Cup, FIFA's anti-doping team paid an unannounced visit to the hotel being used by Brazil's squad Thursday to carry out drug tests on four players.

FIFA's chief medical officer Jiri Dvork led the operation which took urine samples from Juninho, Gilberto Silva, Luisao and Rogerio Ceni. No results were released and FIFA reported that the visit was not based on any specific prior information but as part of its monitoring plan.

The Brazil football federation were also asked to provide documentary proof of the knee injury which forced Barcelona midfielder Edmilson to pull out of the squad on Wednesday.

The swoop is part of FIFA's plan to surprise teams at their World Cup bases in a bid to catch anyone using banned substances.