(CNN) -- Arsenal manager Arsene Wenger has launched an attack on European football's governing body UEFA after being charged with improper conduct for his behavior during Tuesday's Champions League defeat by Barcelona.
Wenger clashed with referee Massimo Busacca at the end of the English team's 3-1 loss to the Spanish champions in the away leg of their last-16 tie in Europe's top club competition.
The Frenchman reacted angrily when striker Robin van Persie was awarded a second yellow card and controversially sent off in the 56th minute of the game for shooting at goal after Busacca had signaled for offside, with the score still 1-1.
"I deny completely any charge. I do not understand where it's from. They (UEFA) do not punish me. It is Arsenal Football Club who has been punished," Wenger told reporters at a press conference on Thursday.
"We are out of the Champions League and have lost one of our big ambitions, and on top of that we have to say sorry when we have done nothing wrong.
"It would be good for UEFA to show some humility, to apologize for what has happened, not charge people who have done nothing wrong."
France midfielder Samir Nasri was also charged for improper conduct after he approached Busacca in the tunnel at the end of the game.
Netherlands star Van Persie said he did not hear the whistle for offside amid the noise of the 95,000-strong crowd at the Nou Camp.
Wenger was immediately outspoken in his criticism of Busacca following the incident, and accused the Swiss official of "killing the game."
Arsenal won the home leg of the tie 2-1 in London, and would have reached the quarterfinals if the score in Barcelona had remained 1-1.
"It is a shame for me that the referee took the decision to send Robin van Persie off. It was the wrong decision," Wenger said.
"This decision frustrated us and everyone who loves football. The first leg was a fantastic advert for football and the second game has been destroyed. People now will only remember the sending-off."
It is the second game in succession that Wenger has criticized a referee's performance, following his condemnation of the officials during the 0-0 home draw with Sunderland last Saturday.
The exit from the Champions League came just nine days after the Gunners' heartbreaking last-minute English League Cup final loss to Birmingham.
Wenger had further bad news for Arsenal fans when he confirmed that skipper Cesc Fabregas had been ruled out of Saturday's FA Cup quarterfinal clash with Premier League leaders Manchester United.
"He had a recurrence of his hamstring and will be out for the next game, maybe for the next two games," Wenger said of the Spaniard, who returned from injury to face his boyhood club Barcelona.
Goalkeeper Wojciech Szczesny will also miss the trip to Old Trafford, after the Polish player sustained a finger injury 18 minutes into the Barcelona game and had to be substituted.
"He has a dislocated finger with a tendon problem," Wenger said. "He had a scan on Wednesday but we need the assessment of a specialist to see where we go from here. He is out for a while, for how long I cannot tell you."
With Manuel Almunia now the club's only fit goalkeeper -- Lukasz Fabianski is also out injured -- Wenger may be forced to search for a replacement on an emergency loan.