More clubs concerned - Blatter

The Blues have been banned from buying players in the next two transfer windows after being found guilty of irregularities over the move of former Lens teenager Gael Kakuta to Stamford Bridge in 2007.

"We have now had a case (Chelsea) to analyse. It has been done by a committee with a judge and representatives of many clubs. That has now been settled," Blatter said. "There are clubs now who are looking at their books, some have even announced that a certain player has no contract with them and he is an amateur. They have done this to try to make sure that the player does not come under the jurisdiction of congress."

Chelsea insist they have done no wrong and are appealing to the Court of Arbitration for Sport in Lausanne.

UEFA president Michel Platini and Blatter have been vociferous in their denunciation of what they have respectively described as "child slavery" and "child trafficking".

The two governing bodies are seeking to close loopholes under EU law that allow players under the age of 18 to move throughout Europe.

"The case we have just decided on is one with a player going from France to England," added Blatter. "But most of the cases we have on our desk are from Africa to Europe or South America to Europe.

"They are taken at 14 or 15 years old with clubs saying that their parents are going too. But they get put into another family, and what happens to them?

"One out of say 20 has a chance to go on in their career. The others are left, and they need to be protected.

"There is an age limit in the FIFA statute that stops a player being transferred internationally until he is 18. The European Union is different, it is 16."