THE HAGUE — The Dutch government yesterday vowed tough measures against what a leading politician called "the arrival of jihad in the Netherlands" after a death threat to a Dutch lawmaker was found spiked with a knife to the body of a slain filmmaker by his radical Muslim attacker.
A five-page letter released Thursday night by the justice minister forced political leaders — including Amsterdam's Jewish mayor and members of parliament — to take on bodyguards.
The document, attached to the body of filmmaker Theo van Gogh, was titled "An Open Letter to [Aayan] Hirsi Ali," referring to a Somali-born member of parliament. She had scripted Mr. van Gogh's latest film, "Submission," which criticized the treatment of women under Islam.
Miss Hirsi Ali, who calls herself an ex-Muslim, has gone into hiding.
"Death, Ms. Hirsi Ali, is the common theme of all that exists. You and the rest of the cosmos cannot escape this truth," the letter said.
"There will come a day when one soul cannot help another soul. A day that goes paired with terrible tortures, ... when the unjust will press horrible screams from their lungs.
"Screams, Ms. Hirsi Ali, that will cause chills to run down a person's back, and make the hairs on their heads stand straight up. People will be drunk with fear, while they are not drunken. Fear will fill the air on the Great Day," the letter said.
"I know definitely that you, Oh America, will go down. I know definitely that you, Oh Europe, will go down. I know definitely that you, Oh Netherlands, will go down. I know definitely that you, Oh Hirsi Ali, will go down," it said.
Deputy Prime Minister Gerrit Zalm agreed with comments by other politicians who called Mr. van Gogh's slaying a declaration of Islamic jihad, or "holy war."
"We are not going to tolerate this. We are going to ratchet up the fight against this sort of terrorism," he said. "The increase in radicalization is worse than we had thought."
Among measures under consideration is an emergency law to enable authorities to revoke the Dutch nationality of dual citizens suspected of terrorist activity so that they can be deported.
Mr. Zalm said the intelligence service, which already has expanded since the September 11, 2001, terrorist attacks in the United States, would receive more funding to help it monitor potential terrorist recruits.
The suspected killer in the van Gogh case, a 26-year-old Dutch-Moroccan national, was arraigned on six terrorism-related charges.
Mr. van Gogh, a descendant of 19th-century Dutch painter Vincent van Gogh, was fatally shot and stabbed Tuesday while cycling down an Amsterdam street. The remains of the provocative social commentator and author, whose throat was slashed in the attack, will be cremated Tuesday in a public service.
The slaying is testing already strained relations between the ethnic Dutch population and the Muslim community. There are about 300,000 Moroccan immigrants in the Netherlands out of a population of 16 million.
Mr. Zalm said talks were ongoing with Muslim groups over how to avoid a violent backlash against Muslims.
Arsonists are believed to have set fire to a mosque in the central Dutch city of Utrecht, police spokesman Peter Keijzers said. There were no reports of injuries.
Jozias van Aartsen, parliamentary speaker for the nationalist People's Party for Freedom and Democracy (VVD), the second-largest party in the government of Prime Minister Jan Peter Balkenende, issued a statement that called Mr. van Gogh's slaying tantamount to a declaration of war.
"The jihad has come to the Netherlands and a small group of jihadist terrorists is attacking the principles of our country," he said. "I hope the Netherlands will now move beyond denial and do what is fitting in a democracy — take action.
"These people don't want to change our society, they want to destroy it," he said.
The terrorist threat left by Mr. van Gogh's killer carries the ideology of a terrorist movement, Takfir wal Hijra or "Repentance and Flight," which advocates isolation from what it calls the sinful world, Dutch press reported.
Chief prosecutor Leo de Wit said the suspected killer, identified only as Mohammed B., faces at least six terrorism-related counts, including charges of murder and "participating in a criminal organization with terrorist characteristics."
The suspect, wounded in the leg in a shootout with police, has refused to talk to investigators. He was arrested with a note in his pocket titled "Drenched in Blood."
Authorities arrested eight other suspects in Mr. van Gogh's slaying and are looking into any links between the suspects and foreign terrorist groups.
Two suspects were released, Mr. de Wit said yesterday. Six will be charged with conspiring to commit murder, he said.
Prosecutors said all are Islamic radicals of North African ancestry. Four also were arrested Oct. 23 on suspicion of plotting a terrorist attack but were released for lack of evidence. Justice Minister Piet Hein Donner told parliament the four had contacts with a suspect in last year's Casablanca bombings.