Two Ukrainian citizens who have long worked for Russian intelligence have been identified as the suspects behind two acts of sabotage on Poland's rail network, Polish Prime Minister Donald Tusk has said.
One of the two suspects had already been convicted in absentia of acts of sabotage in western Ukraine, Tusk told Poland's parliament, the Sejm.
On Monday, Tusk visited the scene of an explosion near Mika, south-east of Warsaw, which damaged the railway line leading to the Ukrainian border, calling it "an unprecedented act of sabotage".
Another incident further down the line near Pulawy forced a crowded train to stop suddenly and damage was found to overhead cables.
Polish authorities had initially said there was a very high chance that acts of sabotage had been ordered by a "foreign service".
