SANAA — A car bomber and gunmen dressed in army uniforms attacked Yemen’s Defense Ministry compound in the capital Sanaa on Thursday, Dec. 5, killing at least 52 people and injuring over 100, in the worst attacks in Yemen in 18 months.

No one has claimed responsibility for the attack. But the country has been grappling with a security threat by al Qaeda-linked militants, who have repeatedly attacked government officials and installations over the past two years.

Soldiers gesture along a road leading to the Defence Ministry’s compound as smoke rises after an attack, in Sanaa December 5, 2013. REUTERS/Mohamed al-Sayaghi

Security forces retook the compound after killing most of the attackers, the Defense Ministry said in a statement on its website.

A medical source and a ministry official said the gunmen had pulled at least two foreign employees, a Western doctor and a Filipina nurse, into the hospital courtyard and shot them dead in front of local staff.

The attack began as ministry employees were arriving to work in the morning. Avehicle exploded at the compound’s gate, two sources inside the ministry said. The ministry’s official statement made no reference to a suicide attacker.

“The attack took place shortly after working hours started at the ministry, when a suicide bomber drove a car into the gate,” a Defense Ministry source said.

The massive blast shook the bustling Bab al-Yemen neighborhood on the edge of Sanaa’s old city, a warren of market stalls and stone tower houses decorated with stained glass windows and ornate plasterwork.

Plumes of smoke billowed over the area, where the country’s central bank is also located.

Ambulance sirens and gunshots were heard after the blast as a second vehicle entered the compound carrying armed men dressed in Yemeni army uniforms and exchanged fire with soldiers.

Yemeni President Abd-Rabbu Mansour Hadi later visited the compound, met senior military officials and ordered an investigation into the attack.