England goalkeeper Joe Hart has given his teammate Dele Alli a warning after the midfielder was caught on TV cameras raising his middle finger.
The Tottenham Hotspur star could face punishment from FIFA if referee Clement Turpin includes the incident in his post-match report.
Alli has claimed that he aimed the rude gesture at teammate Kyle Walker as a "joke" in the second half of England's 2-1 victory over Slovakia.
"The world is watching and Dele appreciates that," Sky Sports News quotes Hart as saying. "He is a young expressive guy who is trying to get to the peak of his game and sometimes he is going to do things that not everyone is going to agree with.
"I think we all know what has gone on - no one has got hurt from it, let's be honest. Luckily and hopefully it was after 9pm and after the watershed. Kids are watching, Dele appreciates that. I'm sure it will be dealt with in the right way."
England require two more points from their final two qualifiers to make it into next year's World Cup finals in Russia.
Danielle Joynson
