Hacking collective Anonymous claim to have targeted the Israeli government and other finance websites, with more than 44 million hacking attempts made on websites since Wednesday, the day the country began its bombing of Gaza.
The group apparently posted a video message, saying the Israeli government had "ignored repeated warnings about the abuse of human rights" and warned "we intend to seize control of your cyberspace."
"Our hearts are with the women, children and families that are suffering at this very moment, as a direct result of the Israeli Governments misuse of its military.
"Cyber war has been declared on Israel cyber space and you will see exactly what we are capable of. Israel, the angel of death has been called to your cyberspace. We are Anonymous. We are legion. Expect us and Respect us."
Finance minister Yuval Steinitz said in a press statement before the weekly cabinet meeting on Sunday that only one attempt had caused damage, and the site had gone down for around 10 minutes. He refused to name which site had been successfully targeted.
He said: The ministry's computer division will continue to block the millions of cyber-attacks. We are enjoying the fruits of our investment in recent years in developing computerised defence systems."
He said most of the attacks gave come from inside Israel and the Palestinian territories. Of the attacks, most were on defence-related websites, 10m on the site of Israel's president Shimon Peres and 7m on the foreign ministry website.
The Bank of Jerusalem was also targeted.
A follow-up statement from the group said they had obtained the personal data of five thousand Israeli officials, with names, ID numbers and personal emails leaked online.
Between Sunday evening and Monday morning the death toll has risen to 84 people in Gaza, Al Jazeera reported, including two child killed in Sajyla, east Gaza, and one in Zeitoun, Gaza City.
UN Secretary General Ban Ki-Moon is heading to Cairo to begin tentative talks of a ceasefire, hoping to preempt a ground invasion by Israel into Gaza.