A statement, emailed to the London-based newspaper on Sunday, said: “Abu Hafz al-Masri Brigades struck a mortal blow after having kept Jewish intelligence agents under surveillance and determined that five of them were in two synagogues in the centre of Istanbul.”
The Abu Hafz al-Masri Brigades - al-Qaida, named after one of its killed fighters, warned in a statement of more attacks around the world.
Saturday's car bombs, which targeted two synagogues in the heart of Istanbul, killed at least 23 people and injured some 300 others.
“We say to the criminal Bush and his valets among the Arabs and foreigners, in particular Britain, Italy, Australia and Japan: you will see the cars of death with your own eyes in the centre of the capital of tyranny," read the statement.
“They will not be limited to Baghdad, Riyadh, Istanbul, Djerba, al-Nasiriya, Jakarta," the statement said, reeling off a list of previous deadly bombings in its warning to US President George Bush.
Abd al-Bari Atwan, the editor of the newspaper, confirmed to Aljazeera that the statement was sent in an email.
"The statement said that they carried out the operations
after they found out that Mossad agents were working at the
synagogues and therefore they bombed them," he said.
Earlier, a Turkey-based Islamist group, the Islamic Great Eastern Raiders/Front (IBDA/C) claimed responsibility in a statement to the state-run Anatolia news agency.
An investigation established that bombers carried out the double attacks.
Israeli investigators are also reportedly investigating the attacks. Police have detained three people, including two women, in connection with the blasts, private television channel NTV said in a report officials have not confirmed.
Turkey has been Israel's chief regional ally since 1996 when the two nations struck a military cooperation accord, much to the anger of Arab countries and Iran. It was the first Muslim country to recognise Israel after it was created in 1948.