The suspect, named only as “Marcin K.,” has been remanded in custody for three months following a court order, public broadcaster Polish Radio's IAR news agency reported, citing the National Public Prosecutor's Office.
According to Stanisław Żaryn, spokesman for Poland’s security services chief, the 43-year-old man "carried out commissioned tasks, including providing the Russian secret services with information and materials related to the military, as well as a Polish citizens and other entities."
"We are talking about data essential for Russian activities in and to the detriment of the Republic of Poland," Żaryn said, as quoted in English on gov.pl website.
He added that the "detainee pleaded guilty to charges."
The suspect could face up to 10 years in prison if convicted, the niezalezna.pl website reported.
Source: IAR, niezalezna.pl, gov.pl