A suicide bomber and gunmen wearing army uniforms have attacked Yemen's Defence Ministry, killing 52 people and injuring 162 others.
The explosions at the compound in the capital Sanaa were the worst single attack in Yemen in 18 months.
Yemen's Higher Security Committee said the dead included doctors, nurses and patients, and said some of those killed were Germans.
The country has been grappling with al Qaeda-linked militants who have repeatedly attacked government officials and installations over the past two years.
No one claimed responsibility for the attack, but a Yemeni expert on Islamist militant affairs said the "suicide nature of the attack" pointed to al Qaeda, Reuters reoprts.
The US-allied country shares a long border with Saudi Arabia, the world's top oil exporter, and the branch of al Qaeda that is based there has plotted attacks against Western targets.
The attack on Thursday began as ministry employees were arriving for work when a vehicle exploded at the compound's gate.
The massive blast shook the bustling Bab al-Yemen neighbourhood on the edge of Sanaa's old city, a warren of market stalls and stone tower houses.
Security forces retook the compound after killing most of the attackers, the Defence Ministry said in a statement on its website, making no reference to a suicide attacker.
Medics and a Defence Ministry official said the gunmen pulled a Western doctor and a Filipina nurse into the hospital's courtyard and shot them in front of local staff.
A medical source who works at one of the hospitals where some of the victims were taken told Reuters a total of two female Yemeni doctors, a Filipino surgeon, a Western doctor and four foreign nurses from India and the Philippines were gunned down.
The United Nations condemned the attack, calling on all parties to cooperate with the investigation, the spokesperson for Secretary General Ban Ki-moon said in a statement.