REPORTING FROM JERUSALEM -- Earlier this week, a computer hacker broke into an Israeli sports website and redirected viewers to a page linking to a file claiming to contain personal and credit card details of 400,000 Israelis. Credit card companies said the lists actually compromised about 15,000 valid credit cards, and the Bank of Israel announced the situation was under control.

But authorities considered it a wake-up call. And Tuesday's assault on credit card numbers may be just the tip of the iceberg.

Angered that Israeli media belittled his handiwork, the person claiming responsibility for the hack released another 11,000 card numbers and, in a post, said there are a lot more -- about 1 million sets of numbers.

And the hacker claims to have more surprises, too, including documents from military contractors and the makers of surveillance equipment.

In an online statement, the hacker calls himself OxOmar. He says he is 19, based in Riyadh and claims to belong to a group named Group-XP, the "greatest Saudi Arabian hacking team."

"It's a payback," OxOmar wrote in an email interview to the popular Israeli news site Ynet. "Israel attacks and kills innocent Palestinian people; they do genocide," he said. He intends to "harm Israel for now financially and socially by creating long queues, and crisis and panic."

Yoram Hacohen, director of the Israeli Law, Information and Technology Authority, has told Israel media that this case should be regarded as a cyber attack.

The Saudi teenager says he broke into more than 80 sites to gather information. Now many online shopping sites are reporting a 25% drop in business.

Israel's government announced the establishment of a National Cyber Directorate last summer after a malfunction at a cellular phone carrier cut service to nearly a third of the country, giving authorities a preview of what a real cyber terrorist attack on critical infrastructure could look like. The directorate is not operational yet.

The Knesset's Science and Technology Committee will hold an emergency meeting Tuesday to discuss the cyber attacks. Lawmaker Ronit Tirosh, who heads the committee, said Israel must prepare for cyber threats and "stay ahead of those trying to use Internet-terror against Israel."