DUBAI (Reuters) - Al Qaeda leader Osama bin Laden threatened the European Union with grave punishment on Wednesday over cartoons of the Prophet Mohammad.

Osama bin Laden sits during an interview with Pakistani journalist Hamid Mir (not pictured) in an image supplied by the respected Dawn newspaper November 10, 2001. REUTERS/Hamid Mir/Editor/Ausaf Newspaper for Daily Dawn

In an audio recording posted on the Internet, Bin Laden said the cartoons were part of a “crusade” in which he said the Catholic Pope Benedict was involved.

The message was released on the fifth anniversary of the U.S.-led invasion of Iraq.

The cartoons were first published by the Danish daily Jyllands-Posten in September 2005 but a furor erupted only after other papers reprinted them in 2006.

At least 50 people were killed in the protests against the publication of the cartoons, which Muslims say are an affront to Islam. Newspapers which have reprinted the cartoons argue they are defending the right to media freedom.

Bin Laden’s message was entitled “The Response Will Be What You See, Not What You Hear”, according to the password-protected Ekhlaas Web, which carries messages and statements from al Qaeda-affiliated groups around the world.

The banner message appeared in bright red, labeled “urgent” with plain Arabic text. It carried no picture of the Saudi-born militant leader nor the insignia of al Qaeda’s media arm As-Sahab, which usually releases his videos and audio tapes.

The message apparently is the first by bin Laden since November 29 when he urged European countries to end military participation with U.S. forces in the Afghan conflict.

The al Qaeda leader, blamed for the September 11 attacks on U.S. cities, issued a number of messages late last year after a hiatus of well over a year raised speculation that he might be dead or incapacitated.

Bin Laden, who is believed to be hiding in remote areas between Pakistan and Afghanistan, has tended to release messages to mark significant dates or events.

On September 7, 2007, bin Laden appeared in a videotape marking the sixth anniversary of the September 11 attacks and said the United States remained vulnerable despite its economic and military power. He then eulogized a September 11 hijacker in an al Qaeda tape that appeared on the anniversary date itself.

Later the same month bin Laden vowed to retaliate against Pakistani President Pervez Musharraf for the killing of a rebel cleric and a raid on his mosque.

Bin Laden is blamed for masterminding a series of attacks on U.S. targets in Africa and the Middle East in the early 1990s.

His wealthy family has disowned him and he has been stripped of his Saudi citizenship.