The suspect, identified only as Paweł G. under Polish privacy laws, was arrested in cooperation with prosecutors and placed in pre-trial detention for three months, Żurek said in a post on X.
According to the National Public Prosecutor's Office, prosecutors have charged Paweł G. with three offences allegedly committed between May 28 and September 20, including participation in an organised criminal group involved in terrorist offences, promoting Nazi and fascist ideology and inciting hatred on national, ethnic, racial and religious grounds.
A second charge concerns "publicly inciting hatred" on those grounds and "promoting a fascist and Nazi system of government."
The third concerns "preparing to kill multiple people in a terrorist attack."
The prosecutor's office said evidence gathered during the investigation, particularly the results of a search of the suspect's home and examinations of his phones and other electronic devices, indicated a high probability that he had committed the alleged offences.
Paweł G. denied the charges and refused to give an explanation, the prosecutor's office said.
A court ordered his three-month detention at the prosecutors' request.
The authorities said weapons, explosives and Nazi symbols were found at his home.
The offence of "preparing to kill multiple people" carries a maximum prison sentence of 15 years, according to prosecutors.
The prosecution service also said a case involving two other people believed to have worked with the suspect had been transferred to family and juvenile courts.
Jacek Dobrzyński, spokesman for the minister coordinating Poland's security services, said on X that Paweł G. was from Siemianowice Śląskie, a city in southern Poland.
"Fascinated by Nazi ideology, he was preparing a terrorist attack in which many people were to die. He planned to purchase weapons and military equipment," Dobrzyński wrote.
Dobrzyński said the case was another example of "the radicalisation of young people capable of committing serious crimes."
The agency said on Friday that it had detained two 16-year-olds who maintained online contacts with extremist groups linked to neo-Nazi propaganda, violence and an interest in terrorist attacks.
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Source: IAR/PAP