Hacking collective Anonymous launched on February 9 a distributed denial of service (DDOS) attack on the website of the Croatian presidency after incumbent Ivo Josipovic defended the Anti-Counterfeiting Treaty Agreement (ACTA).

The attack had lasted for about one hour before the website's operation was restored, local daily Dnevnik said.

It was the latest in a string of cyber-attacks in Eastern Europe following the signing of ACTA by 22 European Union member states in late January.

On February 5, Anonymous hacked the website of Bulgarian music industry group Prophon, defacing it with a message saying that "this domain has been seized by Anonymous under section #14 of the rules of the Internet". The website's front page was restored later in the evening of the same day.

Public opinion in Eastern Europe has been strongly opposed to ACTA, which equates digital copyrights infringement to the counterfeiting of physical goods and, online freedom groups say, opens the door to strict policing of online content.

Poland was the first country to see thousands of people march in protest against the treaty. Further protests have been scheduled for February 11 across the region, Bulgaria included.

Polish prime minister Donald Tusk said on February 6 that his government had made insufficient consultations before signing the agreement and announced that he was suspending the ratification process. Two days later, Czech prime minister Petr Nečas said his government would do the same, The Prague Post reported.

Slovak economy minister Juraj Miškov said on February 6 that ACTA contained a lot of vague formulations and offers many interpretations that pose a potential risk of undesired outcomes, echoing similar criticism from privacy and online freedom watchdogs.

"I won't support an agreement that would curtail basic human rights in any shape or form, particularly the right to freedom and privacy and that will superimpose copyright protection over these rights," he said, as quoted by The Slovak Spectator.

In Bulgaria, Prime Minister Boiko Borissov said that the country's position would be finalised following a wide public discussion, but stopped short of suspending ratification. However, MEPs from Borissov's party GERB would vote against the ratification of ACTA in its current form, according to a statement on February 10.

European Parliament, which has been critical of the secretive nature of ACTA's drafting negotiations, is expected to vote on the treaty in June. If it rejects the treaty, then it would invalidate EU's participation as a signatory party, releasing EU member states from any obligation to ratify the treaty.