Italian authorities are investigating anti-Israeli protests that marred a march in Milan commemorating the 61st anniversary of Italy's liberation from fascism, a prosecutor said Friday. Armando Spataro, an anti-terrorism prosecutor in the northern city, said a number of people have been placed under investigation for incitement to commit a crime, causing damage and holding an unauthorized demonstration. Spataro refused to release information on the number of those investigated or their nationality, saying only that police had identified them as having taken part in Tuesday's protests, during which demonstrators trampled and burned Israeli flags and shouted slogans in support of the Palestinians. The protests happened on the sidelines of a Liberation Day commemorative march and were apparently prompted by the presence in the march of Israeli flags in honor of members of the Jewish Brigade, an infantry unit that helped liberate Italy. Commemorations are held throughout Italy on the April 25 national holiday in honor of the partisan uprising that began on that day in 1945 and ended with the execution of Fascist dictator Benito Mussolini. Italian politicians joined Jewish leaders and the Israeli ambassador to Italy in harshly condemning the flag burning as having marred the celebration. Center-left leader Romano Prodi, who will lead Italy's incoming government, called it a "vile demonstration of intolerance." Vatican newspaper L'Osservatore Romano wrote Wednesday that "to offend a flag means to offend the people for whom it is a symbol, and therefore in this case it was an offense to the entire Jewish people, precisely on the day in which we celebrate liberation from their infamous oppressors."