Arsenal manager Arsene Wenger called for the introduction of blood tests to stop players doping.
The Frenchman had claimed he had seen "many" teams use performance-enhancing substances throughout his career.
Wenger said he was unhappy with the current level of testing, expressing surprise at the lack of positive tests.
"I'm not satisfied with the level of testing because I believe blood tests should be done," he told beIN Sports.
"If you want to go into a bit more sophistication you have to do blood checks.
"Urine checks are superficial and not deep enough to say absolutely sure that we have no doping problem in football.
"I think no and I wish no but on the other hand, can you have 740 football players at a World Cup and come out with zero alert on any doping? It’s a little bit surprising.
"I hope it is true but I think to be completely sure about it, you want to go into deeper tests."
Wenger said players should be heavily punished for doping, calling for an immediate contract termination for those who test positive.
"Look, you have to come to the facts," he said.
"There are two reasons why a player is doped. First, on personal initiative. That means he hides to his club that he doped because he’s scared to lose his place, because he wants to impress, because he has an individual or personal reason to enhance his performance.
"Or it is organised by the club to dope some players and enhance the performances because they are not ready or not good enough or because they have a special competition.
"In most cases, I think, you have to make the player feel responsible for the club as well.
"That means, he cannot be only punished if he’s guilty of having doped because it’s too difficult to prove that it’s a club initiative or a personal initiative so the clubs have to be responsible for the doping of the players individually as well and tell them before the season starts, 'Look, for any doping control, your contract is completely finished because the club suffers the consequences.'"
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