"That's scandalous and the best way to make Croatians disgusted with the EU," Milanovic said, adding the EPP letter showed how one lobbied in Brussels.

He was speaking during a parliamentary discussion on an SDP initiative to give Kosor a vote of no confidence, after the secretary general of the ruling Croatian Democratic Union (HDZ), Branko Bacic, said the HDZ received the EPP's support and quoted from the statement which said, among other things, that "Milanovic is in Brussels politically irrelevant."

"This letter grossly encroaches upon Croatia's internal affairs and comes from an irresponsible nonentity," Milanovic said, adding the letter was sent by the EPP secretary, a technical person, and not a statesman, and that the HDZ should "not deal with its complexes like this."

"Those who beg in Brussels and buttonhole such nonentities to write such statements are paying you lip service, Mrs Kosor, and you know what that is. Don't do that," said Milanovic.

"It is very well known who the secretaries in Brussels are, who is who in Brussels and who I, as president of the SDP, can and can't reach," he added.

"I'm not often in Brussels. I'm there when there are important meetings and I don't take part in the adoption of important decisions, as you don't either, because I'm not from a member country. But while there, I talk with people who are the top of the executive authority in their countries," said Milanovic.

The EPP, which has a majority in the European Parliament, today extended full support to the Croatian government and Kosor in relation to the vote of confidence in the Croatian Parliament.

Commenting on Milanovic's statements in parliament earlier today, EPP secretary-general Antonio Lopez-Isturiz said, "I would like to point out that he often participates in low-level meetings in Brussels with no impact in the EU decision-making process. For all intents and purposes, Mr. Milanovic is in Brussels politically irrelevant."