I believed something like this was impossible in this day in age, in the European Union, in the 21st Century

Belgian Prime Minister Guy Verhofstadt

"This is a deep tragedy for those close to him, for his loved ones and for our country and our democracy," said acting Dutch Prime Minister Wim Kok.

Many were disturbed that Fortuyn, shot to death as he was leaving a radio interview, could have become a target.

Belgian Prime Minister Guy Verhofstadt told journalists while in Macedonia that he was "extremely shocked" by the shooting.

"I believed something like this was impossible in this day in age, in the European Union, in the 21st Century," he told the Associated Press news agency.

British Prime Minister Tony Blair warned against violently targeting politicians, regardless of their political beliefs.

"No matter what feelings political figures arouse, the ballot box is the place to express them," he said.

Far-right response

Politicians on the far right also expressed their dismay at the killing, with some quick to place blame on the left for inciting "hatred".

Many are stunned that such a high profile politician could have become a target

Frank Vanhecke, president of Belgium's extreme-right Vlaams Blok party, said that the killing was yet another incident of what he described as increasing threats to politicians on the far right end of the political spectrum.

"We are shocked but not surprised by what has happened," he told French news agency AFP.

"Throughout Europe and particularly in The Netherlands and Flanders, we have faced a climate of hate and even calls for violence against politicians who question political correctness, just like Mr Fortuyn had done," he added.

'Unacceptable'

His sentiments were echoed by Bruno Megret, head of France's extreme-right National Republican Movement (MNR).

Violence is unacceptable no matter how seriously you disagree with another's political viewpoint

Austria's Freedom Party spokesman Karl Schweitzer

"If it was politically motivated, this criminal act shows to what extent certain hysterical positions like those shown by the French left over the past 15 days can incite hatred," he told AFP.

However a spokesman for Austria's far right Freedom Party said that increasingly wide divide between the two political spectrums had created a volatile political environment.

"The way things have been polarised recently is wrong," Karl Schweitzer told AFP.

"Violence is unacceptable no matter how seriously you disagree with another's political viewpoint."