A group of about 50 Italy fans clad in all black turned their backs in apparent protest during Israel's national anthem before a Nations League match in neutral Hungary.
The Italy fans also held up an Italian flag with the word, "Liberta" (Freedom) on it on Monday. There were black slashes on other banners put up by the "ultra" supporters.
Israel has moved its home games to Hungary because of the conflict with Hamas.
Hungary Prime Minister Viktor Orbán has close ties with Israel Prime Minister Benjamin Netanyahu and has long promoted Hungary as the safest country in Europe for Jews. Orbán has banned Palestinian solidarity protests, arguing they present a threat to public safety.
The same group of Italy supporters who turned their backs during the anthem also chanted against Italian anti-fascist activist Ilaria Salis during the first half, Italian daily Corriere della Sera reported. Salis was freed from house arrest in Budapest in June after facing charges for allegedly assaulting far-right demonstrators.
Salis was released after being elected as a new member of the European Parliament for the Italian Green and Left Alliance.
Salis became a hot-button political issue in Italy after images emerged of her handcuffed and shackled in a Hungarian courtroom where she faced trial.
The Israel-Italy game was being played at Bozsik Arena in Budapest, while Belgium's 3-1 win over Israel on Friday was played in Debrecen, Hungary. Friday's match was a home game for Belgium but the Belgian soccer federation said in July “no local authority in Belgium considers it possible” to stage a game against Israel for security reasons.
Italy is slated to host Israel in Udine on October 14, although Udine's city council has not endorsed the match and a pro-Palestinian protest has been scheduled for the same day in the northern city.