Athens: Hackers attacked the central Bank of Greece to protest the corrupt international financial system, warning that there will be more cyber attacks across the globe, sources said on Wednesday. The attack was carried out on Tuesday during a holiday in Greece and caused a disruption of the bank's website for about six hours, local media reports said, based on a video posted on social media by the international hacker activist group, Anonymous. The central bank has not confirmed the attack yet. It is not the first time that Anonymous has targeted Greek financial institutions. The Greek financial ministry and other ministries were targeted in the past. Anonymous said Tuesday's attack was against "global corrupt financial institutions", and more attacks will follow over the next month against central banks and other financial organisations including in India, the US and Brazil.