An Al-Qaida suicide bomber on Monday blew himself up killing the commander of the southern military region Muhammad Salim Qatan in Yemen's portal city of Aden, a senior official at the interior ministry said.
The bomber was a Somali and the attack occurred while the commander was on his way to work, the official said.
Qatan led military operations to drive Al-Qaida militants out of their strongholds in Abyan province over the past few months.
Yemen's army retook control of Zinjibar, the capital, Jaar and Shuqra, which they seized last year.
The forces have continued to pursue militants in nearby provinces, forcing them to retreat from their main stronghold Azzan in Shabwa province.
Hundreds of militants including senior leaders have been killed since a US-backed offensive began two months ago.
After leaving their strongholds in Abyan, they vowed to retaliate through attacking US targets and observers said Al-Qaida will turn to its old style: suicide bombings and covert operations.
Observers said Al-Qaida will carry out deadly attacks in retaliation for the severe blows in Abyan and other areas in Yemen.
In the past few days, security director was killed in Hadramout and anther escaped an assassination attempt in Taiz.