ADEN-- Unidentified gunmen opened fire and killed a senior officer of Yemen's Criminal Investigation Department (CID) in the southern port city of Aden on Monday, a government official said.

The CID officer identified as Fahmi Hakami was gunned down by gunmen riding a motorcycle in the Mansoura neighborhood of Aden, he said.

The government source based in Aden said that the "drive-by shooting attack happened after the officer left the CID building in Aden."

Meanwhile, the Deputy Minister of the Vocational Education survived an assassination attempt when gunmen hurled a grenade on his house in Lahj province.

No group has yet claimed responsibility for the drive-by shooting attack in Aden and the assassination attempt that took place in neighboring southern province of Lahj.

But the Yemeni government source accused militants of the Yemen-based al-Qaida branch of being behind the terrorist incident in Aden.

Military officials loyal to the United Arab Emirates, mosque preachers and clerics are frequently targeted in Aden either by drive-by shootings or by roadside bombings conducted by terrorist groups.

Aden is considered as the temporary capital of Yemen. The Saudi-backed Yemeni government has been there since 2015.

Over the past two years, the al-Qaida in the Arabian Peninsula (AQAP) and other terrorist groups including the Daesh were active in southern Yemen.

The impoverished Arab country has been locked into a civil war since the Iranian-backed Shiite Houthi rebels overran much of the country militarily in 2014, seizing all northern provinces including the capital Sanaa.

In March 2015, Saudi Arabia led a military coalition of Arab forces, backed by the United States, to intervene in Yemen's conflict to back the government of exiled President Abd-Rabbu Mansour Hadi.

Yemen is facing severe humanitarian crisis, with seven million Yemenis being on the brink of famine and 2,000 people killed by cholera.