Hacktivism group Anonymous has launched a series of cyber attacks against websites in Israel following its assault on Gaza.
The hackers said their operation "OpIsrael" had either damaged or completely erased the sites of over 650 private and public institutions that included the Bank of Jerusalem.
Hackers have carried out data bombardments on several Israel sites leading to homepages being defaced with messages in support of Hamas and the Palestinians.
The hackers posted personal data that include names, addresses, and phone numbers of five thousand Israeli officials online.
Anonymous said: "For far too long, Anonymous has stood by with the rest of the world and watched in despair the barbaric, brutal and despicable treatment of the Palestinian people in the so called 'Occupied Territories' by the Israel Defence Force,"
"But when the government of Israel publicly threatened to sever all Internet and other telecommunications into and out of Gaza they crossed a line in the sand." Anonymous said.
The group threatened Israel with the "unbridled wrath of Anonymous" if it goes ahead with the Internet cable, telecom cut and military operations in Gaza.
The attacks on the Israeli sites follows an attack on the online operations of major US banks that include, Wells Fargo, Bank of America, JPMorgan Chase and Capital One Financial, which were disrupted in a series of attacks.
In August this year, Anonymous had claimed that it attacked and forced offline a number of the UK government's websites in response to its treatment of Julian Assange.
In May 2012, Anonymous had claimed responsibility for hacking the Department of Justice website, grabbing data in the process.