LIVERPOOL, England (Reuters) -- Forward Ryan Babel faces punishment from Liverpool over the mocked-up picture of referee Howard Webb that he posted on Twitter, manager Kenny Dalglish said on Friday.

The Dutchman has already accepted an improper conduct charge from the Football Association for the doctored photograph which showed Webb in a Manchester United shirt after Liverpool's 1-0 defeat at Old Trafford in the FA Cup on Sunday.

Webb, who took charge of last year's World Cup final between Spain and Netherlands, awarded United a penalty in the opening minute of the game and Babel posted the picture with the comment: "And they call him one of the best referees? That's a joke".

Dalglish warned players to be more careful.

"You know the repercussions if you say or do something that's contentious," he told a news conference.

"It was a bit tongue in cheek and it wasn't his creation. He never drew it, he forwarded it.

"He's apologised unreservedly to the referee. I'm sure the club will probably take some action I would've thought and that should be it finished with."

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