Mariusz Krason of the Appellate Prosecutor's office said the suspect is a 45-year-old Polish citizen who does not belong to any political party, Thenews.pl reported.
"Simply put, the man feels that the social and economic situation in the country is going in the wrong direction and virtually all government positions are being occupied by people which he described as 'foreigners,'" Krason said.
Four other people connected to the suspect have been questioned.
The unnamed suspect is accused of engaging in the construction of explosive devices and made a number of trips to Warsaw to study the area around Poland's Parliament as well as the route marked out for the president's Nov. 11 Independence Day march, prosecutors said.
A search of several sights across Poland has netted four tons of explosive materials, including TNT, fuses with a mobile phone attached, wires and detonators.
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