Yemeni state television has aired horrific images of an Al-Qaeda-claimed assault on a defence ministry complex in Sanaa showing the assailants executing civilians and medics in cold blood.
The footage, taken from surveillance cameras, were aired on Yemen TV late on Wednesday and show the attack and its aftermath.
Al-Qaeda in the Arabian Peninsula has claimed the attack that took place on December 5 in broad daylight and killed 56 people.
The images show a car packed with explosives detonated at the gate to the complex, sending soldiers, medics and civilians gathered inside the compound running for cover.
After the blast, heavily armed militants dressed in combat fatigues are seen wandering through the corridors of the complex, shooting anyone they see, including a wounded female nurse who appears to be looking for help.
Another gunman in military uniform calmly approaches a group of people huddled in a corridor after the initial blast, before pulling a hand grenade from his jacket and hurling it at them.
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The group scrabbles for cover, before the grenade explodes and smoke blocks the screen.
Elsewhere in the complex, a man with a young girl are seen looking for a place to hide. Their fate is not shown, while a doctor is seen running to rescue a wounded man before one of the attackers shoots both dead.
A preliminary report into the attack had said most of the attackers were Saudi.
Investigators had already said the assailants wore military fatigues and penetrated the sprawling Sanaa complex in the confusion created when the suicide bomber rammed his vehicle into the gate.
They said the bodies of 12 attackers were recovered after security forces retook the area.
Among the dead were medics from the Philippines, Germany, Vietnam and India. Civilian patients as well as soldiers were also killed, Yemen's supreme security committee had said.