Sepp Blatter has told World Cup referees to protect the players and clamp down hard on elbowing.

The president of soccer's ruling body FIFA said on Monday that this was the only instruction he gave the match officials when he visited them in Frankfurt last Tuesday.

Speaking at a news conference following a two-day meeting of FIFA's executive committee, Blatter referred to elbowing as a "devil".

He said: "I gave them only one instruction, to protect the good games and to protect the good players and to pay special attention to the devil that has come into our game, elbowing.

"That is when a player jumps and does not keep his arms to his side or by his body."

Blatter said he hoped to see plenty of goals and good football with the top players protected.

He said there were 21 approved, tried and tested trios of officials to control the 64 World Cup matches and that they had undergone more intensive training than in the past.

"There are more people there with the referees to prepare them and to test them than there are referees, and they have been tested at every level."

The World Cup starts on Friday.