Polish intelligence services are investigating a hacking attack on the country’s railways, Polish media say.
Hackers broke into railway frequencies to disrupt traffic in the north-west of the country overnight, the Polish Press Agency (PAP) reported on Saturday.
The signals were interspersed with recording of Russia’s national anthem and a speech by President Vladimir Putin, the report says.
Poland is a major transit hub for Western weapons being sent to Ukraine.
Saturday’s incident occurred when hackers transmitted a signal that triggered an emergency stoppage of trains near the city of Szczecin, PAP reported.
About 20 trains were brought to a standstill, but services were restored within hours.
Read more: BBC News