Unidentified gunmen killed a security official in Yemen's southern port city of Aden on Sunday, a government official told Xinhua.

"Two masked gunmen opened fire from silenced weapons and killed Salah Hujaili near his house in Aden's neighborhood of Mansourah," the local government source said on condition of anonymity.

Hujaili, who died instantly at the scene, was working as a director for the Criminal Investigation Department in Mansourah, the source added.

No group has yet claimed responsibility for the attack which is blamed on the Yemen-based al-Qaida branch.

Politicians and high-ranking southern security commanders have been the prime targets of the kidnapping incidents or armed attacks in recent months.

Yemen 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.