"The player of Partizan Belgrade, Milan Gurovic, who has a tattoo on his upper left arm with the image of Draza Mihajlovic, has publicly stated that during Goodyear League matches in Croatia he will not conceal his tattoo," Mehun said.
"The Law on Public Assembly prohibits such behaviour at public gatherings. This also qualifies as illegal behaviour under the Law on the Prevention of Riots at Sporting Competitions and the Law on Violations of Public Order and Peace," Mehun said.
Mehun said that the Ministry's police directorate had promptly notified the Basketball Association of its decision, the Croatian Foreign Ministry and the Embassy of Serbia and Montenegro in Zagreb.
Mehun said this was the first time such a measure had been applied to a foreign basketball player.
The ministry would have reacted the same way if a Croatian player carried visible Nazi or any other symbols instigating hatred or violence on racial, ethnic or religious grounds, Mehun said.
Zagreb's basketball club "Cibona" and Partizan are to play on Sunday. Gurovic was previously not included in teams playing in Croatia.
The head of the regional Goodyear League, Josip Bilic, said he did not want to prejudge the outcome of the case.
"The laws of every country are above individuals, clubs or associations and everybody should abide by them," Bilic said, adding that the case would be discussed on Monday.