ADEN: Gunmen shot dead an army colonel and a car bomb injured a senior intelligence officer in Yemen's main port city of Aden on Tuesday, a security official said.
Yemen's armed forces are fighting against an Islamist insurgency across southern Yemen after militants took advantage of political chaos during the "Arab Spring" in 2011 to seize control of several towns.
Western governments see Yemen's stability as vital for international security because of the country's location next to main oil exporter Saudi Arabia and alongside important crude shipment routes.
They fear a further descent into chaos as the country attempts to unite opposing regional and political factions may create more space for al Qaeda in the Arabian Peninsula to operate.
Yemen's al Qaeda wing last week claimed responsibility for a suicide attack on a police headquarters, and an offshoot claimed an assault on Yemen's Defence Ministry in which more than 50 people were killed last month.
The gunmen in a pickup truck attacked Colonel Mubarak Lashram, an official in military supplies department, killing him and badly injuring another soldier, before fleeing.
The intelligence officer, Colonel Saleh al-Qadhi was driving between two main districts in Aden when a parked vehicle exploded, seriously injuring him, the security official said.
Last week gunmen shot dead Colonel Marwan Muqbili, an intelligence officer, in Aden.
The shootings and bomb attack this year follow a string of similar assaults on security and military officers in southern Yemen over the past year.