Officials in Yemen say four security officers were killed in a series of suspected militant attacks over the past two days.
Three of the killings were carried out in the capital Sanaa by men riding on motorcycles.
The attacks follow aerial strikes that killed 55 al-Qaida militants in southern Yemen. Those strikes reportedly involved U.S. drones.
Al Qaida in the Arabian Peninsula (AQAP) has launched attacks on military targets, tourists and diplomats in Yemen in recent years.
Last week, the group's Yemen branch vowed to carry out more attacks against what it calls "western crusaders."
Some information for this report was provided by AP, AFP and Reuters.