The arrests were made in the early morning hours of Tuesday, Feb.12.

The Danish intelligence agency PET "conducted a police operation at 4.30 a.m. (local time) in the Aarhus region, in cooperation with local police, to prevent a murder linked to terrorism," PET chief Jakob Scharf told the AFP news agency.

PET said three arrests had been made in connection with the case but did not disclose their identities. The three suspects were a Dane of Moroccan origin and two Tunisian nationals.

PET added that it expected the 40-year-old Danish citizen to be released pending further investigation. The Tunisians will remain detained while deportation proceedings are brought against them.

The target of the alleged plot was a 73-year-old cartoonist who drew a picture of the Islamic prophet Mohammed wearing a turban that resembled a bomb.

The image was one of a series of caricatures published by the Jyllands-Posten newspaper in September 2005.

The cartoons initially went unnoticed but were later reprinted outside Denmark, where caused they caused major offense in the Muslim world.

In January and February 2006, Danish diplomatic offices were burned in Damascus and Beirut, and dozens of people died in violent protests.

Sunni Islam prohibits visual depictions of the faith's most important prophet, and insulting representations of Mohammad are considered a grave sin by Muslims in general.

"This has become my life"

The targeted cartoonist and his wife have been under heavy police protection for months and have been frequently moved after the couple received death threats.

In a statement to Jyllands-Posten newspaper, the artist said he feared for his life.

"I've only done my job and I continue to do so," the cartoonist said. "I don't know how long I will live under police protection. But I think the consequences of this crazy reaction will continue as long as I live. It is sad but this has become my life."

The newspaper that published the caricatures said that it had followed the police investigations leading to the arrests with grave concern.

"It is shameful that a man who was doing his job well and in accordance with Danish law and press ethics is rewarded with demonization and concrete murder threats," Jyllands-Posten editor-in-chief Carsten Juste told AFP.

Danish Prime Minister Anders Fogh Rasmussen said he was deeply concerned by the serious nature of the crime.

"Unfortunately, the matter shows that there are in Denmark groups of extremists that do not acknowledge and respect the principles on which Danish democracy is built," Rasmussen said in a statement. "In Denmark, we have freedom not only to think and talk, but also to draw."