"We shall help identify the rioters if the Austrian police request it. We have not yet received any request to that effect," a Croatian police spokesman told Hina on Monday.
Spokesman Krunoslav Borovec said that out of nine arrested rioters, who would be interviewed by a magistrate judge during the day in Kapfenberg, five were members of the Dinamo fan club known as the "Bad Blue Boys".
Those five Croatian rioters and another four Austrians were taken into 48-hour custody as they were involved in riots and attacks against police officers.
Borovec said the Croatian police could not take any measures against them as the riots had taken place in Austria.
The riots erupted after the friendly match, when hooligans threw stones, chairs and bottles at the police in a square by the soccer stadium.
About 30 policemen had to seek medical assistance.
The local police in Kapfenberg believe that about 200 men from Zagreb and about 30 fans of the Rapid club were involved in the riots and that they had agreed earlier on a concerted assault against the police.
Many cars in a nearby parking lot were damaged in Saturday's incidents.