Imprinted into the grass of the Poljud stadium, the swastika was noticeable in the first half of the Group H fixture played without any fans present after the Croatians had been given a one-match ban for prior offences.
"We apologise to all fans watching the game on television, to both teams and to our guests from Italy for the Nazi symbol," Croatian football association press officer Tomislav Pacak told the Balkan country's media.
"As far as we have learned, the symbol was imprinted into the pitch between 24 and 48 hours before the match so that it could be visible during the game.
Euro 2016
Rooney: Hodgson got it wrong at finals
01/08/2016 AT 19:37
"This is sabotage and a felony, hence we expect police to identify the perpetrators and we have also notified UEFA.
"This is a disgrace not just for the HNS but for the whole of Croatia. Neither our coach nor players will comment."
Croatia were already being punished for repeated offences by their supporters, who shouted racist slogans during a 5-1 home win over Norway in Zagreb in March.
That came on the back of incidents in last November's 1-1 draw against Italy in Milan, when visiting Croatia fans twice halted play by hurling flares on to the pitch.

Italy complain after Swastika is found on turf in Croatia.

Image credit: Eurosport

Euro 2016
Hodgson's England 'had the talent to win Euro 2016'
26/07/2016 AT 15:39
Euro 2016
France beat Portugal to make final
21/07/2016 AT 17:19