A segment of a rail line linking Poland’s capital, Warsaw, to the border with Ukraine was blown up over the weekend. Prime Minister Donald Tusk called it an “unprecedented act of sabotage”.

Evidence suggests the blast over the weekend was “initiated by the Russian secret services”, Jacek Dobrzyński, the spokesman for Poland’s security services minister, said after a meeting of the National Security Committee.

The Polish prime minister has said the two people responsible are Ukrainian, that they collaborated with Russian intelligence, have left Poland and are now in Belarus.

In what Prime Minister Donald Tusk called an “unprecedented act of sabotage”, a segment of a rail line linking Poland’s capital, Warsaw, to the border with Ukraine was blown up over the weekend.