Israeli hackers launched successful denial of service attacks the websites of the Saudi Arabian and UAE stock exchanges late last night, responding to Monday’s attacks on several Israeli institutions.

Hacking group IDF-Team claimed responsibility for the attack, warning "lame hackers" that any further attacks on Israeli interests would lead IDF-Team to disable websites for "weeks or even months".

On Monday, the websites of the Tel Aviv Stock Exchange (TASE), the First International Bank of Israel and national airline El Al were all taken offline by denial of service. Arab hacker, 0xOmar claimed responsibilty in an email to Israeli newspaper, Ynet.

The cyber attacks between Arab and Israeli groups has not been limited to denial of service attacks, however. In the past week, an Israeli-aligned hacker has claimed to have stolen the bank account details of ten million Saudis and Iranians.

Going by the name Hannibal, the hacker has also posted a total of 60,000 email and Facebook accounts from the same countries. He claims to be holding 30 million Arab email accounts.

In a statement, Facebook admitted that more than half of the email addresses were associated with Facebook accounts, but claimed that the information did not represent a hack of Facebook. "We have spent time investigating the information [on Pastebin] and have determined fewer than a third of the credentials were valid," a spokesperson said.