A railway track on a line connecting the country with Ukraine was damaged in north-eastern Poland. The damage was noticed by the train driver and reported it to the Mazowieckie Voivodeship police.
The police said that there were two passengers and several workers on the train and none of them were injured.
Polish Prime Minister Donald Tusk said he did not reject the sabotage version.
Later, Deputy Interior Minister Maciej Duszuk said the damage was not caused by the explosion. He gave no other details.
In July, Polish authorities detained 32 people suspected of collaborating with Russian security services to organise acts of sabotage in the country. The criminal group included citizens of Poland, Russia, Ukraine, Belarus and Colombia. According to the Polish Internal Security Agency, the crimes were committed or prepared on the instructions of Russian intelligence officers.
Russia denies accusations of involvement in sabotage and sabotage on Polish territory. The Russian Foreign Ministry calls Warsaw’s claims unsubstantiated and aimed at escalating tension between the countries.