Unidentified gunmen opened fire and assassinated a senior security official in the country's southern port city of Aden on Saturday, a government official said.

The local government source said on condition of anonymity that "Colonel Mohamed Saleh, a senior official of the security department in Aden, was gunned down by unknown gunmen near his house."

He said that the unknown gunmen opened heavy fire from their assault rifles against the security official and killed him outside his house in Aden's neighborhood of Mansourah.

The unknown gunmen fled the area immediately via motorcycles after conducting the assassination incident, according to the source.

On Sunday, two masked gunmen opened fire from silenced weapons and killed Salah Hujaili near his house in Aden's neighborhood of Mansourah.

Hujaili was working as a director for the Criminal Investigation Department (CID) in Mansourah neighborhood, the local Yemeni sources said.

No group has claimed responsibility for the recent assassination incidents yet, but the drive-by shooting attacks were blamed on the Yemen-based al-Qaida branch.

Politicians and high-ranking southern security commanders have been the prime targets in such armed attacks launched by unknown gunmen in recent months particularly in Aden and neighboring provinces.

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

Saudi Arabia leads an Arab military coalition that intervened in Yemen in 2015 to support the government of President Abd-Rabbu Mansour Hadi after Houthi rebels forced him into exile.