Danish police said Tuesday they have arrested three people suspected of plotting to kill one of the 12 cartoonists behind the Prophet Muhammad drawings that sparked an uproar in the Muslim world two years ago.

The arrests were made in pre-dawn raids in Aarhus, western Denmark, "to prevent a terror-related murder," the police intelligence agency said. It did not say which cartoonist was targeted.

However, according to Jyllands-Posten, the Danish newspaper that first published the drawings on Sept. 30, 2005, the suspects were planning to kill its cartoonist Kurt Westergaard.

"There were very concrete murder plans against Kurt Westergaard," said Carsten Juste, the paper's editor-in-chief.

Westergaard is the cartoonist who drew Muhammad with a bomb in his turban, one of the most controversial of 12 cartoons in the series.

Later in the day, Denmark's intelligence service said it was questioning two Tunisians and a Danish citizen of Moroccan origin in connection with the plot.

It said the Tunisians were to be expelled from the country and the Dane was released after questioning.

There was not enough evidence to remand the suspects in custody because the security service had intervened at a very early phase in the plot, it said.

Prime Minister Anders Fogh Rasmussen said he was "deeply concerned by these suspicions of a very serious crime, which unfortunately demonstrates that there are extremist groups in Denmark that do not recognise or respect the basic principles of society."

"In Denmark, we are free not only to think and speak as we please, but also to draw what we want. And the government will protect this freedom of expression," he stressed.

The cartoons were reprinted in a range of Western publications, and they sparked deadly protests in parts of the Muslim world.

Islamic law generally opposes any depiction of the Prophet, even favourable, for fear it could lead to idolatry.

Westergaard, 73, and his wife Gitte, 66, had been living under police protection and have had to change homes frequently because of the murder plans, Jyllands-Posten reported.