Israel on Friday blamed Al Qaeda for a series of bomb attacks in Egypt's Sinai peninsula that left at least 37 people dead and scores missing.
"According to our first information, it appears to be the an international terror attack with the hallmarks of Al Qaeda, Israel's deputy defence minister Zeev Boim said.
However, a group calling itself 'Islamic Unity Brigades' claimed responsibility on Friday for the attacks.
The attacks occurred on Thursday as the Red Sea coast of the southern Sinai was packed with Israeli holidaymakers celebrating the final day of the Jewish festival of Sukkot.
"Four of your martyrdom-seeking brothers (suicide bombers) carried out this heroic operation against a den of prostitution and corruption," said a statement posted on an Islamist website whose authenticity could not be confirmed.
The previously unknown group said the attack was in revenge for Israel's assassination last March of Sheikh Ahmed Yassin, founder of the Palestinian Islamist movement Hamas.
