Poland has arrested a Russian man who was hired by Moscow to kill a Ukrainian-American citizen in Warsaw, Polish Prime Minister Donald Tusk said on Thursday. The Russian was detained on August 7 and had been recruited to kill a man who was “inconvenient to the Putin regime”, Tusk told journalists. The Russian embassy in Warsaw did not immediately respond to an emailed request for comment. Moscow has regularly dismissed accusations by European powers of attacks, saying the West is stoking...