The Qaeda-linked Abdullah Azzam Brigades  shared a video on social networks, in which the group reveals how the attack was carried out, vowing to carry on targeting Hezbollah bastions if the party didn't withdraw from the conflict in neighboring country Syria.
The video entitled “the invasion of the Iranian Embassy in Beirut,” which went viral on twitter, depicts an interview with one of the suicide bomber, who reveals that he chose to “martyr to achieve great loses in the enemy's side.”
He notes in a Youtube video that he took part in the clashes that happened in the southern town of Abra, to protect his neighborhood and religion.
Salafist cleric Sheikh Ahmed Al Asir's supporters engaged in armed battles with the Lebanese army in June in the area of Bilal Bin Rabah Mosque and nearby buildings in Abra.
The suicide bomber Hezbollah secretary-general Sayyed Hassan Nasrallah, pointing out that the number of “those who are ready to martyr is greater than the party's members.”
He called on Hezbollah to withdraw from Syria and the release of Islamist inmates in Roumieh prison in order to stop the attacks on the party's stronghold.
The video emerged a day after the army announced the arrest of a Palestinian leader in the Qaeda-linked Abdullah Azzam Brigades and seizing two booby-trapped cars in Beirut and the Bekaa.
Naim Abbas is described as the group's number two man in Lebanon.
At least 23 people were killed and 150 wounded in twin suicide blasts that targeted the Iranian Embassy in Beirut's southern suburbs of Bir Hassan in November.
The powerful explosions just opposite the multi-storey embassy caused chaos, ripping the facades off nearby buildings and setting cars ablaze.
Hezbollah has dispatched fighters to battle alongside the Syrian regime  against rebels seeking the overthrow of President Assad.
The conflict, pitting a Sunni-dominated rebel movement against Assad, has raised sectarian tensions in Lebanon and Lebanese Sunni fighters have also been killed while fighting alongside Syrian rebels.
Lebanese parties are sharply divided over the crisis in Syria as the March 8 alliance continuously expresses its support to Assad, while the March 14 camp voices its support for the popular revolt.