WARSAW — A rail line linking the Polish capital to the eastern city of Lublin and on to Ukraine was blown up Sunday in an “act of sabotage,” Prime Minister Donald Tusk said Monday morning.

Train traffic along the busy route was halted Sunday morning after a high speed Intercity train driver spotted damage to the line, warning nearby trains. “The track might have been destroyed deliberately,” Tusk said Sunday.

Authorities now say they are certain the damage is the result of a planned attack.

“Unfortunately, the worst suspicions have been confirmed. An act of sabotage occurred on the Warsaw-Lublin line, near the village of Mika. An explosive device destroyed a section of the track. Emergency services and prosecutors are working at the site. Damage has also been found on the same line, closer to Lublin,” Tusk wrote on X.

The Polish prime minister did not directly indicate who was responsible, but linked the incident to Russia’s war in Ukraine.

“Blowing up the rail track on the Warsaw-Lublin route is an unprecedented act of sabotage targeting directly the security of the Polish state and its civilians. This route is also crucially important for delivering aid to Ukraine. We will catch the perpetrators, whoever they are,” Tusk said in another post on the same platform.

Maciej Duszczyk, the deputy interior minister, on Sunday warned against immediately implicating Russia.

“Russia is not so powerful that every arson attack, every situation of this kind, is provoked by Russia. However, this cannot be ruled out or dismissed in any way,” he told the Polsat news channel.

The Warsaw-Lublin train route is one of country’s busiest, linking the capital to the biggest city in eastern Poland and on toward Ukraine. The damaged section remains closed but service continues on parallel tracks, public broadcaster TVP Info reported.

Defense Minister Władysław Kosiniak-Kamysz said that the Polish military will be examining the 120-kilometer stretch of track running to the border with Ukraine.

Since Russia’s full-scale attack on Ukraine in February 2022, Poland has been on high alert for cases of foreign espionage and sabotage both on the ground and in cyberspace, which authorities have linked directly to Russia or its close ally Belarus. 

Authorities have arrested multiple people on suspicion of planning sabotage or mapping critical infrastructure. Last month, two Ukrainian nationals were detained on suspicion of spying for a foreign intelligence service.

Other recent incidents involved an alleged Belarusian refugee authorities accused of being a Russian operative, a fire set in a shopping mall near Warsaw and an alleged attempt to sabotage a railway station by leaving an unmarked railcar on tracks used by passenger trains.

“The adversary has begun preparations for war,” the Polish chief of general staff, Gen. Wiesław Kukuła, said Monday. “It is building a certain environment here that is intended to undermine public trust in the government and institutions such as the armed forces and the police. This is to create conditions conducive to potential aggression on Polish territory.”