Suspected Al-Qaeda gunmen killed an intelligence officer in the south Yemen port city of Aden, a security official said.
Colonel Marwan al-Maqbali was leaving his house on Thursday in Al-Qalua neighbourhood when he was fired on from a car carrying gunmen "suspected of belonging to Al-Qaeda", the official said.
Two bullets hit Maqbali who died before reaching hospital, and his assailants escaped, the source added.
Al-Qaeda in the Arabian Peninsula (AQAP) has been blamed for most of the increasingly common hit-and-run strikes targeting military personnel and officials.
The armed group rarely claims responsibility for such attacks, but did admit being behind a brazen daylight assault on the defence ministry in Sanaa that killed 56 people on December 5.
AQAP took advantage of a decline in central government control during Yemen's 2011 uprising to seize large parts of the territory across the south.
The fighters were driven back in June 2012 by a military offensive and the group has been further weakened by US drone strikes.
AQAP is considered by Washington to be the most dangerous affiliate of the Al-Qaeda network.