Relatives of those killed in the brazen terrorist attack in Yemen's capital collected their bodies from a hospital Friday to prepare them for burial.
At least 52 people were killed and many others were wounded in a suicide-bomber attack Thursday on a Yemeni military hospital adjacent to the Defense Ministry in Sana'a.
Militant Islamist group Al-Qaida in the Arabian Peninsula has claimed responsibility for an attack in a statement issued on Twitter Friday. The group's media arm said the Defense Ministry complex was targeted because it, as the group claims, it "accommodates drone control rooms and American experts."
The Associated Press quoted Yemeni military investigators Friday as saying that 12 militants, some of them Saudi nationals, were responsible. The news agency says a Yemeni military committee issued a report that set the death toll at 56, with another 215 wounded.
The attack is described as having been carried out in two stages. First, the report said, attackers disguised in military uniform drove a car packed with explosives into the complex, blew it up, and then split into two groups. One swept through a military hospital while the second group attacked a laboratory. Both killed everyone they found.
It was the deadliest attack in more than a year.
At least seven of those killed were foreign nationals, including medical personnel from Germany, India, the Philippines and Vietnam.
Casualties included civilians and military and medical personnel. Yemen's Saba news agency said two doctors from Germany, two from Vietnam and another from Yemen were killed, as well two female nurses from the Philippines and one from India.
Yemeni President Abd-Rabbu Mansour Hadi lvisited the compound and ordered an investigation into the attack.
In Washington, a National Security Council spokesperson said the U.S. condemns the operation and "extends its deepest condolences to the families of the victims of this brutal attack."
U.N. Secretary General Ban Ki-moon's special adviser for Yemen, Jamal Benomar said that "such criminal acts seeking to terrorize Yemenis will only strengthen their resolve to continue on their path of peaceful change".
Saudi King Abdullah sent a message of condolences for the victims to President Hadi.
Yemen has been plagued by instability since its longtime president, Ali Abdullah Saleh, handed over power after a popular uprising in 2011.