Poland railway blast was unprecedented act of sabotage, says Donald Tusk

Polish PM vows to catch the perpetrators, regardless of who their backers are' after blast on track used for deliveries to Ukraine

Poland's prime minister, Donald Tusk, has described an explosion along a section of railway line used for deliveries to Ukraine as an unprecedented act of sabotage" that could have led to disaster.

It came as a statement from public prosecutors on Monday evening said an investigation had opened regarding acts of sabotage of a terrorist nature [...] committed on behalf of a foreign intelligence service against the Republic of Poland."