Cairo: In a rare public apology, the militant leader of al-Qaeda's branch in Yemen has said that one of his fighters disobeyed orders and attacked a hospital attached to the Defence Ministry during a December assault that killed 52 people.

Qassim al-Rimi, commander of al-Qaeda in the Arabian Peninsula, said in a video posted on militant websites that the attackers were warned in advance not to enter the hospital within the complex, nor a place for prayer there. But he said one fighter did.

An image grab taken from footage, taken from surveillance cameras, aired by Yemen's state television shows an armed militant dressed in combat fatigues inside the defence ministry complex. Credit:AFP

"Now we acknowledge our mistake and guilt," Mr al-Rimi said in a video released late Saturday by al-Qaeda's media arm al-Mallahem. "We offer our apology and condolences to the victims' families. We accept full responsibility for what happened in the hospital and will pay blood money for the victims' families."

The apology seemed prompted by Yemen state television earlier broadcasting a video showing a gunman attacking doctors and other hospital staff. Several al-Qaeda jihadis tried to dismiss the video as fake on militant websites, but the outcry apparently embarrassed the al-Qaeda branch to the point of issuing an unusual expression of regret from the group.