Poland on Friday said it had detained a Belarusian man on suspicion of being part of a "Russian spy ring" which it claimed planned to derail trains carrying aid to Ukraine.
Poland, a key ally of Ukraine, had previously reported arrests in the investigation, including that of a Russian ice hockey player in June who was also held on espionage charges.
"Belarusian Mikhail A. took part in reconnaissance of military facilities and ports. He also carried out propaganda activities for Russia," Polish Interior Minister Mariusz Kaminski said on Twitter, recently rebranded as X, adding the man was the 16th person held in connection with the alleged spy network.
The Polish government said Friday that the Belarusian came to Poland in 2021 and "maintained contacts with citizens of the Russian Federation, with whom he was meeting in St. Petersburg and Crimea."
"The man often changed the means of communication and was destroying traces of his criminal activities," the statement said, adding that the 39-year-old pleaded "partly guilty."
It also said the alleged spy ring's actions included "preparations for derailing trains carrying aid to Ukraine" as well as "inciting sentiments against the Ukrainian nation or providing aid to Ukraine by Poland."
Poland, a NATO member, has recently raised fresh concerns about possible provocations coming from neighboring Belarus, which now hosts Russian mercenaries from the Wagner Group.
Earlier this week Warsaw announced two Belarusian military helicopters had violated Polish airspace, which prompted Poland's decision to reinforce its eastern border.
In a statement published Friday, the Polish foreign ministry called on Minsk "to urgently clarify the incident... and to stop all provocations along the Polish-Belarusian border."