Stanislaw Zaryn, the deputy minister coordinator of the security services, broke the news on Twitter.
Since Russia's invasion of Ukraine on February 24 last year, the Polish security services have seized 20 people suspected of working for Russian or Belarusian intelligence.
A statement released by Zaryn's office said that one of the men had been detained and charged with working for Russia. A court ordered his arrest for three months.
The foreign national, detained last Tuesday, is charged with performing reconnaissance activities for Russian intelligence.
"Evidence indicates that he gathered information, among other things on critical infrastructure in the (northern) Pomorskie and Kujawsko-Pomorskie provinces and on the actions of (security) services and bodies responsible for security," said the statement, adding that the man had admitted to the crime.
"The man had carried out missions ordered by the Russian (intelligence) service since at least January 2023," the press release continued.
On March 1, another foreign man was detained and charged with working on behalf of the Belarusian intelligence services.
It is believed that he gathered reconnaissance data on facilities key to Polish security and connected with the armed forces. He was placed under three months' arrest by a court in the eastern city of Lublin. (PAP)