Polish law enforcement officials have launched an investigation into the burning of a Ukrainian flag in Warsaw on November 11. Ukrainian Ambassador to Poland Andrii Deschytsia announced this to Ukrainian News Agency. Polish Foreign Affairs Ministry spokesperson Joanna Wajda announced on Twitter that the Polish Foreign Affairs Ministry received a diplomatic note from the Ukrainian side on Monday. Unidentified people burned a Ukrainian flag during a nationalist march commemorating Poland's 98th independence anniversary in Warsaw on November 11. As Ukrainian News Agency earlier reported, President Petro Poroshenko wished Poland peace and prosperity on its Independence Day.