After Croatia scored a 2-0 victory and secured its place in the 2014 Brazil championships, the defender took to the microphone on the pitch at the Maksimir Stadium in Zagreb on Tuesday night and chanted "For the homeland!", to which fans responded "Ready!".
"We are in the process of analysing the different match officials' reports and gathering information. We cannot comment further for the time being," a FIFA spokesman told the portal.
Simunic said after the match, "Those who have a problem with those chants should read and learn some history. "If someone has something against it, that's their problem. I'm not afraid."
However, the day after, he said he had meant nothing wrong: "The thought that anyone could associate me with any form of hatred or violence terrifies me... For a Croat raised outside his homeland, home means love, warmth and a positive fight. Maksimir, Zagreb, Croatia - that's my home. If anyone understood my chants differently, negatively, I hereby deny any political context of my statement which was driven solely by my love toward my people and my country, and not by hatred and destruction".