After a cyber-attack by a hacker claiming to be Saudi, Israel has vowed a strong response.

"(Such an attack is) a breach of sovereignty comparable to a terrorist operation and must be treated as such," Deputy Foreign Minister Danny Ayalon said in a speech quoted by BBC . "Israel has active capabilities for striking at those who are trying to harm it, and no agency or hacker will be immune from retaliatory action."

"Israel has active capabilities for striking at those who are trying to harm it, and no agency or hacker will be immune from retaliatory action," said Ayalon, according to Reuters.

Reuters quoted Hamas spokesman Sami Abu Zuhri as calling the hack "a new form of resistance" and encouraged "Arab youth to ignore these cowardly Israeli threats and to use all means available in the virtual space to confront Israeli crimes."

The Arab news network Al Arabiyya has reported that Saudi banks are tightening their security against an anticipated attack by Israeli hackers.

"The security systems departments in several Saudi banks embarked on an extensive campaign on Saturday to increase security on their transactions and guarantee wider monitoring of their websites."

If retaliation comes, whether it will be prosecuted by Israeli government technicians or by independent, or semi-independent, hackers is hard to say. Over the last several years, responsibility for country-to-country cyber-attacks has been hard to track, with some orchestrated by governments directly and others being amateur efforts.

Ayelet Noff, founder of Israeli PR firm Blonde 2.0, whose father was a member of parliament in the Knesset, told ReadWriteWeb she doesn't believe any attack will be conducted directly by the government.

"Israel as a country will not retaliate," she said, "however, it is more than likely that Israeli hackers will retaliate in the cyber space."

Although the hacker claimed to have compromised 400,000 online identities by hacking a sports website, Naked Security said the credit card companies claim the figure is closer to 6,000. Only a couple of hundred dollars was charged on the hacked cards before they were cancelled.

Israeli communications base photo by Adam Jones