Liverpool winger Ryan Babel on Monday became the first player to be charged with improper conduct by England's Football Association over a Twitter posting.

Babel posted a digitally altered picture of referee Howard Webb wearing a Manchester United jersey after being angered by decisions in his team's FA Cup loss on Sunday.

Babel also wrote on Twitter: "And they call him one of the best referees. That's a joke."

The FA confirmed in a statement: "The charge relates to comments and images published by the player on Twitter concerning referee Howard Webb."

Babel has until Thursday to respond to the charge. He could be fined or banned from matches by the FA.

While Babel has since deleted his comments about Webb and the link to the manipulated picture, it was still visible on the image uploading service he uses.

In Liverpool's 1-0 loss, Webb ruled that defender Daniel Agger fouled United's Dimitar Berbatov 30 seconds into the third-round match. Ryan Giggs converted the following penalty kick.

Webb also ejected Liverpool captain Steven Gerrard for a challenge on Michael Carrick in the 32nd minute.

As Babel's messages spread on Sunday night, he tried to limit the damage.

"Sorry Howard Webb!" he tweeted. "My apology if they take my posted pic seriously. This is just a emotional reaction after losing an important game."

Babel's contentious messages came a day after Kenny Dalglish was appointed Liverpool manager. The Scot is the first Premier League manager to have a Twitter account, although he hasn't posted on it since getting the Anfield job.

But at a news conference earlier Monday, Dalglish had urged the FA not to take any action against Babel.

"Maybe I've been out of the game too long but let's see if they can find a sense of humor," said Dalglish, whose first stint as Liverpool manager ended in 1991. "He apologized straight away."

And Dalglish quipped about the picture: "I don't think he's clever enough technically to have drawn that up himself."

Babel's case has highlighted the perils of sportsmen using social networking sites to communicate with their fans.

Marvin Morgan, a forward with fourth-tier club Aldershot, was suspended, fined and placed on the transfer list last week over a tweet.

After being booed by fans when he was substituted during a match, Morgan wrote: "Like to thank the fans who booed me off the pitch ... I hope you all die."

Premier League club Newcastle is issuing guidelines to its players about Twitter use after defender Jose Enrique annoyed manager Alan Pardew last week by revealing to followers that he would miss a match at Tottenham through injury.