The Polish-Russian war of words over World War II has taken an ugly turn, with the Polish president refusing to attend a Holocaust memorial in Israel and his PM accusing the Soviet Union of delaying the liberation of Auschwitz. President Andrzej Duda has refused the invitation to the World Holocaust Forum at Yad Vashem on Thursday, in protest over Russian President Vladimir Putin being invited to speak at the event while he was not. Instead, Duda will preside over the memorial ceremony in Auschwitz on Monday – to which his government deliberately did not invite Putin.