Yemeni officials say 52 people have been killed in a suicide car bombing and a subsequent attack by gunmen on a military hospital adjacent to the Defense Ministry in the capital, Sana'a.
A statement by the Supreme Security Commission said 167 people were also wounded in Thursday's attack, the deadliest in more than a year.
Casualties include civilians as well as military and medical personnel at the hospital. 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.
There was no immediate claim of responsibility. But Sana'a-based political analyst Abdulghani al-Eryani told VOA the attack "bears all the hallmarks of an al-Qaida operation." He said the motive was clear.
"Their main interest is in getting high visibility and attracting international media attention - that's their instrument for recruitment, not just in Yemen but around the world."
Al-Eryani said the operation was likely an inside job because former president Ali Abdullah Saleh had cultivated relationships with al-Qaida and other terrorist groups, allowing them to infiltrate his security forces.
"It is well known, and I have spoken often about it, that [Mr. Saleh] cultivated al-Qaida and used them to extort financial benefits from the U.S., Saudi Arabia and other countries."
Officials said the bomber rammed a car packed with explosives into one part of the complex as attackers on foot opened fire with automatic rifles on another.
Yemeni President Abd-Rabbu Mansour Hadi later visited the compound, met senior military officials and ordered an investigation into the attack.
Reuters reported that a relative of Mr. Hadi was among those killed.
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."