Fortuyn was killed after giving an interview to the 3FM radio network in Hilversum, about 10 miles (16 kilometers) southeast of Amsterdam. Police said they had arrested a Dutch national suspected of the murder, but said his identity and motive were still unknown.

He was heading for his car when he was shot six times. Paramedics treated Fortuyn where he fell at the entrance to the building, pumping his chest to try and revive him. Hours after the shooting, Fortuyn's body lay where he was shot, covered with a white sheet. Prime Minister Wim Kok confirmed Fortuyn's death.

Dutch television said the 54-year-old former academic and columnist, who led an openly gay lifestyle, was shot in the head, neck and chest. The attack came nine days before national elections, and opinion polls had predicted Fortuyn would lead one of the largest parties in parliament.

"After this assassination, Pim Fortuyn is gone," Kok said in The Hague after breaking off a campaign engagement. "This is a deep tragedy. I am shocked. This is a deep tragedy for those close to him, for his loved ones and for our country and our democracy."

It is the first time in modern history that a Dutch political leader has been assassinated. "These are things you thought were just not possible in the Netherlands," said Ad Melkert, Kok's successor as leader of the ruling Labor Party and its candidate for prime minister. "It's a low-point for our democracy."

Fortuyn had dictated debate during the campaign with verbal attacks on the country's growing Muslim population and strident criticism of the national government. He called Islam a 'backward' culture and laid claim to leadership of the Netherlands' perennially vacant political right.

The radio reporter who interviewed Fortuyn said he saw a man with a gun - apparantly the assailant - being chased and captured by policemen with dogs. Other witnesses said the gunman was chased by at least four people after the shooting. Police had no immediate comment.

"I saw Pim Fortuyn lying on the ground with a bullet wound in his head," said television reporter Dave Abspoel.

Fortuyn had recently expressed fears for his safety. A few weeks ago, protesters threw two cream pies laced with urine in his face.

"It's a scandal that the Justice Department did not take action after the pie incident," said his lawyer, Oscar Hammerstein. Harry Mens, a close friend who talked with Fortuyn on the phone in the morning, told Dutch television Fortuyn was worried about threats made in recent days against him.

"He did not want to return to Rotterdam this evening," Mens said.

Fortuyn's rise mirrored a right-wing resurgence in several European countries, lately highlighted by the anti-immigrant Jean Marie Le Pen's surprise showing in the first round of French presidential elections. Le Pen was soundly defeated in Sunday's run-off vote by incumbent Jacques Chirac.

Nevertheless, Fortuyn had dissociated himself from Le Pen and other European extreme right leaders.

Fortuyn's platform seemed out of place in the Netherlands, which has a reputation for liberalism. It was the first country to legalize gay marriages, regulate prostitution, approve and control euthanasia, and tolerate the over-the-counter sale of marijuana in hundreds of "coffee shops". Fortuyn's popularity had exposed a deep vein of suspicion of immigrants in Europe's most densely populated country, about 2 million of whose 16 million people are not native Dutch. About 800,000 are Muslims.

Several political parties called for a halt in the election campaign, but there was no immediate demand to postpone the vote. The head of the Liberal Party, VVD, Hans Dijkstal, stopped his party's campaign.

In the Netherlands, most political leaders travel without bodyguards, often using public transportation. The only exception was Kok, as head of government. Fortuyn, however, had his own bodyguards and his party headquarters in Rotterdam were always guarded.

Last March, his newly formed party stunned the nation by sweeping 35% of the vote in local elections in Rotterdam, a port city with a large immigrant population.

Police have cordoned off Fortuyn's house in Rotterdam, where he often met supporters and gave interviews. Followers lay bouquets outside the house.

Fortuyn's hard-hitting campaign against immigration and what he called "the mess" created by Kok's eight-year coalition, dominated the campaign and refocused the issues.

British Prime Minister Tony Blair cancelled a scheduled visit to the Netherlands on Wednesday. Britain's Foreign Secretary Jack Straw said he was "profoundly shocked" by the murder.

Belgian Prime Minister Guy Verhofstadt told Belgian media on a visit to Skopje, Macedonia that he was "extremely shocked" by the shooting.

It is believed to be the most prominent killing of a European politician since Swedish Prime Minister Olof Palme was gunned down in Stockholm in 1986.