Captain Steven Gerrard has revealed that every member of England's World Cup squad has been warned about their conduct by coach Fabio Capello.

England begin their Group C campaign against the United States on Saturday amid suggestions that Wayne Rooney could be a target for opposition provocation due to his fiery temperament.

Monday's warm-up victory over local side Platinum Stars was overshadowed by a row involving Rooney and the match referee over his on-pitch conduct.

Gerrard has now admitted that every member of the 23-man squad has been told to keep their emotions in check by Capello.

"Wayne understands we need him on the pitch - he's a very important player - and every player has been warned by the manager and coaching staff to channel their frustration in the right way and not get involved with the referees or with any silly challenges," he said.

"We've had experience of losing big players at important times and we need to keep everyone on the pitch. This tournament is going to be difficult enough, so if we lose someone it will only complicate things further."

Capello's warning came after Rooney was given a stark warning from local referee Jeff Selogilwe after an angry tirade aimed at the official during Monday's 3-0 warm-up victory.

The striker came on as a half-time substitute but was booked after his introduction and told by Selogilwe to calm down.Subscribe to Football FanCast News Headlines by Email