"The fight against corruption in Croatia certainly doesn't end with this case. It will go on, which means that new investigations and new arrests can be expected. I don't want to prejudge and because of the secrecy of the investigation, I can't speak about concrete cases nor about who they refer to," Karamarko was quoted as saying.

He said Sanader could be extradited from Austria in a few days, but that the proceedings could drag on for several months, depending on whether Sanader agreed to the extradition or not.

Speaking of a previously announced project of a regional centre for fighting organised crime, Karamarko said such a centre practically existed, despite the fact the Croatian and Serbian police forces "aren't sitting in the same building."

"What is crucial is that our joint investigation teams, which already exist, work efficiently," he said, adding the establishment of a regional centre was not pressure or a condition set by the international community, but an original initiative by him and Serbian Interior Minister Ivica Dacic.

Karamarko said it was already agreed that the centre would be based in Belgrade and headed by a representative of the Croatian Interior Ministry.

"Since criminal groups are expanding their activity throughout the region, we would be very happy if other Southeast European countries joined the centre. We pitched this idea to our colleagues in the region at our informal ministerial meeting in Zagreb in February."

Asked about the possibility of Balkan countries having a joint police, Karamarko said there was no need for that, but that it was necessary to strengthen the cooperation between the national police forces.