Poland will deploy 10,000 troops to guard key infrastructure, including railways, after an explosion damaged a strategic railway section near Warsaw at the weekend, Reuters reports.
The government took the measures after Prime Minister Donald Tusk described the incident as an "unprecedented act of sabotage" and Warsaw publicly hinted at Russian interference.
The explosion affected a line on the Warsaw-Lublin route, part of the Warsaw-Lublin-Hrubieszow corridor, which connects the capital to Ukraine by rail and road and is considered "of crucial importance" to supply Kiev.
Defense Minister Wladyslaw Kosyniak-Kamysz said the army would inspect 120 km of the route to the Ukrainian border. Chief of the General Staff General Wiesław Kukula described the incident as deliberate, warning that "the enemy is creating an environment to undermine trust in state institutions" and creating conditions for "potential aggression on Polish territory".
The National Security Bureau stressed that the situation requires "special monitoring and reliable communication". Meanwhile, European Commission President Ursula von der Leyen warned that threats to European security "are real and growing" and called for urgent reinforcement of the protection of critical infrastructure.
In a separate incident on Sunday evening, a train on the Świnoujście-Rzeszów route was forced to stop about 50 km from Lublin after overhead electrical cables were damaged. It was carrying 475 people, but no one was injured. The incident is also under investigation.
Polish authorities say dozens of suspects in sabotage and espionage have been detained since the start of Russia's invasion of Ukraine in 2022.