"We have been patient with Kajin because of his history in the IDS and because of all the problems he has found himself in," Chiavalon said. He noted that in the last six months Kajin had done everything to have himself expelled from the party.

"Today he violated the Statute and expelled himself from the party. He will be officially struck from the membership roll in accordance with Article 11 of the Statute," Chiavalon added.

Chiavalon would not comment on Kajin's accusations directed against IDS president Ivan Jakovcic, saying that his accusations were at odds with what he had been saying "until a few months ago". "Some people are obviously not for the future," he concluded.

Jakovcic said it was unfair that a political party, alluding to the Social Democratic Party (SDP) of Prime Minister Zoran Milanovic, should "steal a person who until today served as vice-president of another party."

"This says enough of the morality of those people. I don't want to make any further comment. I am fully devoted to the campaign that will follow. After all, I will run in European elections, and as for relations within the coalition, Mr Milanovic will have to give it some serious thought," Jakovcic said.

Jakovcic said that the IDS was not considering leaving the ruling coalition because an IDS member, Tourism Minister Veljko Ostojic, was rated the best minister in public opinion polls.

"We are a responsible party and we will honour our commitments to the coalition partners in full. I will most likely not attend meetings of the coalition partners anymore," Jakovcic said.