The statement said Monday's bombing in Islamabad was carried out to fulfil the promise of terror mastermind Osama bin Laden to exact revenge over the reprinting in Danish papers of a cartoon of Islam's Prophet Muhammad.

The statement, carried on a Web site frequently used by the Islamic militants, said the attack "fulfilled the promise of Sheik Osama Bin Laden, may God protect him, of responding" to the "insulting drawings."

It added that the attack came in defence of the religion and honour of Muslims and warned that if Denmark doesn't apologise for the cartoons, more attacks will follow.

The statement was signed by an al-Qaida commander in Afghanistan, Mustafa Abul-Yazid, and dated Tuesday, but its authenticity couldn't immediately be verified.

It said the attack was carried out by an al-Qaida martyr and thanked Pakistani jihadists who helped prepare and execute the plot.

Many suicide bombings in Pakistan are believed to have been planned in its semiautonomous tribal regions along the Afghan border, where al-Qaida and Taliban militants have found sanctuary and which are the focus of peace efforts.