Unidentified assailants shot dead a senior Yemeni air force officer on Saturday in the eastern province of Hadramawt, where Al-Qaeda remains active despite a government crackdown, a security official said.
The gunman sped off on the back of a motorbike after killing Colonel Yahya al-Umayssi, commander of the air force detachment at the town of Seiyun, in the inland north of the province, an official said.
A witness said that both assailants were masked but that the gunman removed his mask before opening fire, saying: "In the name of God, Allah is great," as he did so.
There was no immediate claim for the attack but loyalists of Al-Qaeda have carried out a spate of assassinations of security officers in the south and east of Yemen in relation for a US-backed crackdown on its network.
Around 70 security officers have been killed in the region in the past two years in attacks attributed to Al-Qaeda, officials say.
Al-Qaeda fighters retreated to mountainous areas of the east after being forced out of urban centres in the south during an army offensive in May 2012.
Al-Qaeda had taken advantage of a weakening of central government control during the 2011 uprising that forced veteran strongman Ali Abdullah Saleh from power to seize large swathes of the south and east.