"Even though there is information of a connection between the 40-year-old and the planners of the plot to murder Kurt Westergaard, it is not possible to submit sufficient evidence in court that he took part in the planning," prosecutor Elsemette Casoe said, according to Danish news agency Ritzau.

Westergaard, 73, drew the cartoon that caused most controversy, depicting the founder of Islam with a bomb in his turban. He told Ritzau he accepted the prosecutor's decision but wanted Denmark to deport two other suspects still in detention who are fighting deportation to their native Tunisia.

"These threats have seriously violated my human rights," said Westergaard, who has been living under the protection of Denmark's Security and Intelligence Service. "I'm a supporter of the Danish judicial system. But I think they should have been deported (immediately). It would have been a relief for me."

The cartoons were reprinted outside Denmark, provoking outrage among Muslims. Three Danish embassies were attacked and at least 50 people were killed in rioting in the Middle East, Africa and Asia.

Last month, al Qaeda took responsibility for a suicide attack on Denmark's embassy in Pakistan that killed at least six people and wounded 20, in revenge for the cartoons.