After a police complaint and a major operation in Croatia and Bosnia and Herzegovina, Croatia's USKOK anti-corruption office has launched an investigation into eight Croatian citizens and one Serbian suspected of smuggling at least 100 illegal migrants.

At last 100 foreigners were transported from Bosnia and Herzegovina to Croatia on 25 occasions, for which the suspects were paid, USKOK said on Thursday.

The Interior Ministry said five Croatian nationals were arrested in Croatia on Wednesday, one Croatian and one Serbian national were in custody from before, and two Croatian nationals were at large.

Police seized from the suspects €78,650, HRK 6,000 and 1,710 Bosnian marks, among other possessions.

USKOK asked a Zagreb County Court judge to set detention for four of the suspects.

Between June and August, USKOK said, two of the suspects arranged with an unidentified person from Turkey the illegal transport of a larger number of foreigners across the Bosnian-Croatian border for €400 per person.

The transport was allegedly organised by the Turk. In Croatia, the migrants were met by the Croatian suspects, who drove them by car to Zagreb, from where they were supposed to go to the Slovenian border.