The Saudi hacker who has been at the forefront of the recent cyber-war against Israel said he will continue to strike Israel until its government will "apologize for their genocide in Palestine and Gaza".

In an email exchange with The Jerusalem Post, 0xOmar claimed that he has joined the forces with a group of pro-Palestinian hackers called "Nightmare" that have claimed responsibility for attacking and shutting down the Tel Aviv Stock Exchange and El Al's websites.

"Yes, I'll keep... attacking and publishing everything related to military or credit cards of normal people," he said.

"I want to hurt/harm Israel in any possible [way]," 0xOmar said "I'll DDOS [carry out denial of service attacks on] important sites, like Tel Aviv Stock Exchange, and currently we're DDOSing Bank Massad," he said, minutes after the bank was affected by a Web attack.

"I'll hack Israeli servers and publish their data, I'll publish credit cards. Imagine every possible cyber-attack, I'll do it. There is no end for it, but if Israeli authorities apologise for their genocide in Palestine and Gaza, I'll reduce attacks," the unnamed hacker said.

The network called "Nightmare Group" targeted the Tel Aviv Stock Exchange and El Al's website earlier this week. A spokeswoman for the stock exchange confirmed the site had come under attack, but claimed the trading systems had not been affected.

"There is someone that has been attacking the Tel Aviv Stock Exchange (TASE) website since this morning," Idit Yaaron told AFP, describing what appeared to be a distributed denial of service attack (DDos).

DDos assaults are a form of cyber-attack that use large numbers of computers to overload a website with requests, forcing it go offline.

Earlier on Monday, hacker 0xOmar, who last week stole and posted credit card details and personal information of 6,000 Israelis online, warned he was going to attack the websites, Israeli newspapers reported.

0xOmar first attack came January 3 when he claimed to have posted details of 400,000 Israeli-owned cards online.

Israel's main credit card companies admitted that 20,000 cards have been hacked.

"This is the beginning of cyber war against Israel, you are not safe anymore," 0xOmar posted on Pastebin last week, urging hackers from across the Arab and Muslim world to target Israel. "We'll hack Israeli servers for different purposes like leaking Israeli data, sensitive and hidden information extraction and defacing websites," he wrote.