Two bombs, timed to go off one after the other, killed two people and injured 12 others in southern Yemen's biggest city, a security official said Monday.
The first bomb exploded outside a sports club in the port city of Aden wounding four people and sending police and rescue units rushing to the scene.
The second bomb exploded once they had arrived, injuring 10 more, including three soldiers. Two of the civilians died of their wounds at the hospital, the official said on condition of anonymity because he was not authorized to speak to the media.
Bombs timed to go off at intervals in order to kill medical and security teams were a hallmark of al-Qaida-linked insurgents in Iraq, where many Yemenis went to fight over the last seven years.
The country's own al-Qaida offshoot has been targeting security forces, most recently in the south's Abyan province, when two gunmen shot dead a policeman Sunday.
In Aden, two policemen and one civilian were injured when a hand-grenade was thrown at a police car.
Al-Qaida in the Arabian Peninsula was formed more than a year ago when Yemen and Saudi militant groups merged. Al-Qaida fighters are believed to have built up strongholds in remote parts of the country, allying with powerful tribes that resent the government of President Ali Abdullah Saleh.
They are also believed to have a presence in the capital city itself and in some other major cities in the south where several attacks in recent years have cast doubt on the government's ability to protect its own backyard.