Geneva: FIFA on Friday announced that they had opened a probe against Australian-born Croatia defender Josip Simunic for his pro-Nazi chants that marred the country`s World Cup qualification celebrations.
"Disciplinary proceedings have been opened," a FIFA spokesman said, declining to make further comment on the player`s case.
It was not clear what penalty Simunic could face.
But various football authorities have adopted an ever-tougher stance against far-right displays, with Greece youth international Giorgos Katidis this year earning a life ban from his home federation for a Nazi salute -- although he has since resurfaced at Novara in Italy`s second tier.
FIFA also opened an investigation against Croatia`s fans for "improper conduct", the spokesman said.
Following Tuesday`s 2-0 home win against Iceland that saw them advance from their World Cup qualifying play-off after a goalless first leg, Simunic took over a microphone at the Maksimir stadium in the Croatian capital Zagreb.
He shouted "za dom" -- Croatian for "for the homeland" -- four times. In response, fans chanted "spremni", meaning "ready".
The chant was used by Croatia`s World War II Ustasha regime, allied to Nazi Germany, which killed hundreds of thousands of Serbs, Jews, anti-fascist Croatians, Roma and others in concentration camps.
On Thursday, Croatian prosecutors said Simunic had been fined 25,000 kunas (3,200 euros, USD 4,400) for inciting racial hatred, adding that the player was aware that the chant symbolised the official salute of Croatia`s totalitarian regime.
Simunic argued that he was motivated purely by his love of the Croatian nation, denying any political intent and saying the emotion of the moment was the only reason.
The 35-year-old Dinamo Zagreb captain was born to Croatian immigrant parents in the Australian capital Canberra.
Football is highly popular in Australia`s Croatian-origin community.
He is among a raft of Australian-born players who have opted for their ancestral home since Croatia joined the international football fold after independence from former Yugoslavia in 1991.
Australia, meanwhile, count big-name players with Croatian roots, such as former captain Mark Viduka.
Simunic has spent the bulk of his career in Europe, joining Germany`s Bundesliga in 1998 and signing to Dinamo in 2011.
He made his Croatia debut in 2001.
His chants were condemned by Croatian President Ivo Josipovic, the government and Milorad Pupovac, leader of the country`s Serb minority.
However, the Croatian Football Federation (HNS) on Friday denied any pro-Nazi connotations.
"Simunic`s behaviour is inappropriate ... the HNS has regulations on players` behaviour and we will react," executive president Damir Vrbanovic told reporters.
However, the federation is "worried by an avalanche of negative comments targeting our player and our view is that his call for cheering was not aimed at remembering the Ustasha," Vrbanovic said.
"Simunic took all this very emotionally and is shocked that someone is linking his gesture with a dark period of the Croatian past," he added, underlining that it was "human to make mistakes."
HNS head Davor Suker -- a former international who was top scorer in the 1998 World Cup, where Croatia finished third -- labelled Simunic`s move an "inappropriate gesture" and voiced regret that it overshadowed Croatia`s qualification.
In the past, the HNS has condemned fans` pro-Nazi attitudes and their use of Ustasha insignia and Nazi salutes.
FIFA and European football`s governing body UEFA have on several occasions punished Croatia for fan racism.
At Euro 2012 in Poland, UEFA fined Croatia 80,000 euros (USD 101,000) in the wake of incidents including monkey chants directed at Italy star Mario Balotelli.