A railway line linking Warsaw to southeastern Poland was damaged by a weekend explosion that the prime minister on Monday called an act of sabotage.

Speaking at a news conference in Warsaw on Monday, Polish Interior Minister Marcin Kierwiński confirmed that an explosion on a railway line casued damage to the tracks.

A train driver on the line between the capital, Warsaw and Lublin, reported track irregularities around 7:40 a.m. Sunday.

Further inspection determined there was damage to a section of track near the village of Mika, about 100 kilometers (62 miles) southeast of Warsaw, officials said.

It wasn't immediately clear whether the explosion and damage occurred late Saturday or early Sunday. Two passengers and several staff members were on the train, but no injuries were reported, officials said.

A second train was damaged separately Sunday and the incident is under investigation, Kierwiński said.

A train on the Świnoujście-Rzeszów route was forced to stop Sunday night about 50 kilometers (31 miles) from Lublin after the overhead electrical cables that powered the train were damaged, Kierwiński explained. There were 475 passengers on board but no injuries were reported.

Tomasz Siemoniak, Polish Minister and Coordinator of Special Services, said "the probability that this is being carried out at the behest of foreign intelligence agencies is very high".

Polish authorities have detained dozens of people over suspected sabotage and espionage since Russia launched all-out war on Ukraine on Feb. 24, 2022. Poland has accused Russia of being behind some of these acts.