At least 52 people were killed and 162 wounded on Thursday by a suicide bombing of Yemen’s Defence Ministry complex in the heart of the capital Sana’a, followed by a gun battle.

The Ministry said many of the dead are doctors and nurses.

The Defence Ministry said attackers exploited a lull in security caused by construction work at the military hospital, ramming an explosive-laden vehicle into the Ministry while another group attempted to storm the building.

President Abdo Rabbo Mansour Hadi’s nephew died in the blast, and his brother remains in intensive care.

There was no immediate claim of responsibility for the attack, the deadliest in Yemen in 18 months.

The Hadi Government, which came to power after the fall of the long-time ruler Ali Abdallah Saleh in February 2012, has been seeking progress and security through a National Dialogue. Issues include the desire of some in southern Yemen for secession, attacks by insurgents, and the demand for autonomy by Houthis in the north.