WARSAW (Reuters) - Polish authorities have arrested a radical nationalist who planned to blow up parliament and had links to the right-wing extremist who murdered dozens of people in Norway last year, they said on Tuesday.
The suspected plot - to detonate a bomb outside parliament when the country's most senior officials were inside - was the first of its kind since Poland threw off Communist rule more than 20 years ago.
It is likely to bring renewed scrutiny on radical right-wing groups inside Poland, which are fiercely opposed to the liberal government, and on the way extremists intent on violence share information with each other across Europe.
"This is a new and dramatic experience," said Prime Minister Donald Tusk, who, according to prosecutors, was one of the intended targets of the assassination plot, along with the president. "This should be a warning."
Prosecutors said the suspect, a 45-year-old scientist who works for a university in the southern city of Krakow, planned to plant four metric tons of explosives in a vehicle outside parliament and detonate it remotely.
The plot had parallels with Anders Behring Breivik, the Norwegian who set off a bomb in Oslo last year and then went on a gun rampage on a nearby island, killing a total of 77 people.
"The would-be bomber did not hide his fascination with Breivik. This should not be ignored," Tusk told a news conference.
The prime minister said that investigators had found practical connections to Breivik too: the Norwegian bought bomb components in Poland, he said, and an analysis of his contacts helped lead Polish intelligence to the suspect.
Authorities in Norway said they had been in touch with their Polish counterparts but gave no details.
Briefing reporters in the Polish capital, prosecutors said the suspect had assembled a small arsenal of explosive material, guns and remote-controlled detonators and was trying to recruit others to help him.
A video recording taken from the suspect, who has not been publicly identified, showed what prosecutors said was a test explosion he conducted, sending up a huge cloud of dust and leaving a large crater in the ground.
"He claims that he was acting on nationalistic, anti-Semitic and xenophobic motives," prosecutor Mariusz Krason said.
"He believed the situation in the country is going in the wrong direction, described the people ruling Poland as foreign and said they were not true Poles."
"He carried out reconnaissance in the neighborhood of the Sejm (parliament). This building was to be the target of the attack," Krason said.
Poland is one of several European countries where far-right groups have become more visible in the past few years, a trend some scholars say is partly linked to hardship caused by the financial crisis.
In Hungary, opinion polls show strong support for the far-right Jobbik opposition party. Greece's ultra-nationalist Gold Dawn is backed by 10 percent of the population.
Most right-wing groups renounce violence, but some on the margins are more radical.
Roger Eatwell, a professor at Britain's Bath University who studies the far right, said though extremists intent on violence did not operate in networks, they do share information across Europe's borders.
"They look at each other through the Internet, they sometimes correspond with each other through the Internet, though they have to be careful because that is monitored," he said. "The bad news is that they are very hard to police."
In Poland, society is polarized between liberals, who back the government, and a substantial number of people who believe the country is neglecting its Catholic roots and succumbing to foreign influence.
A rally in the capital, Warsaw, this month by right-wing nationalists turned violent. Youths in the crowd, some of whom had been chanting anti-Semitic slogans, started throwing flares and stones at police.
Polish prosecutors on Tuesday produced evidence suggesting the suspect was planning a sophisticated attack on parliament.
They showed photographs of pistols and bags of ammunition which they said he had bought in Poland and Belgium. They also showed several vehicle license plates, both Polish and German, which they said had been found among his belongings.
They said the suspect had used his scientific background to assemble the explosives himself. "He is a specialist in the field," prosecutor Krason said.
Officials said that they had found explosive substances including hexogen and tetryl, as well as detonators that could be triggered remotely using a mobile telephone.
The dean of the Agricultural University in Krakow, where prosecutors said the suspect worked, said the man had never given any reason for suspicion.
"It never occurred to us that at our school there could be a person involved in such matters. There were no indications from his co-workers that anything unusual was happening," Roman Sady said.
Additional reporting by Wojciech Zurawski in Krakow, Karolina Slowikowska and Chris Borowski in Warsaw, and Balazs Koranyi in Oslo; Writing by Christian Lowe; Editing by Robin Pomeroy