Polish security authorities are investigating multiple cases of disruption to railway traffic, after unauthorized radio signals stopped several trains over the weekend.
On some of the signals, the Russian national anthem could reportedly be heard in the background.
Poland's railway is the main transport route for international military support going to neighboring Ukraine, which is fighting Russia's aggression. The network also transports Ukraine's agricultural exports to markets further west.
Two men in their 20s were arrested Sunday after they generated intercom signals that halted five passenger trains and one cargo train near Bialystok, in the northeast. Prosecutors have opened an investigation.
Similar “radio-stop” signals briefly stopped some passenger and cargo trains in other regions across Poland over the weekend. In some cases, the Russian anthem could be heard over the intercom, Polish media reported.
Authorities said there was no threat to public security and no one was hurt.
Stanislaw Zaryn, the deputy coordinator of the intelligence services, said over the weekend that the Internal Security Agency, or ABW, was checking whether these could be sabotage cases.
“At this moment, we are not ruling out any scenarios,” he said.
“We know that attempts to destabilize the Polish state have been going on for months,” he said. “Such efforts have been carried out by the Russian Federation in cooperation with Belarus, and for this reason we are not underestimating any signals that reach the ABW.”
Previous cases of minor derailments contributed to the concern over the railway system's vulnerability at a crucial time.
Experts say that the outdated radio communication system renders Poland’s underinvested railways vulnerable to pranks and sabotage at a time when it plays a key role in maintaining transport links with Ukraine. A planned upgrade to a digital communication system has been delayed.
The ABW told The Associated Press on Monday that so far 16 suspects, mostly foreigners, have been arrested on allegations of spying for Russia, including gathering information on the railway system.
