ADEN, Yemen, Oct. 9 (Xinhua) -- An officer of the newly-recruited Yemeni troops was killed by a bomb attack in the southern province of al-Dhalea on Tuesday, a security official told Xinhua.

Muhsen Besbas, an officer of the Yemeni forces recently established by the United Arab Emirates (UAE), was killed outside his house by unknown gunmen, who hurled a grenade toward his car, the security source said on condition of anonymity.

Witnesses said the motorcycle-riding attackers fled the scene shortly after the assassination.

The UAE-backed Yemeni forces are struggling against a surge in drive-by shootings and armed attacks launched by terror groups such as al-Qaida and the Islamic State (IS).

The al-Qaida and IS networks, mostly operating in eastern and southern provinces, have been responsible for many high-profile attacks against security forces in the country.

The U.S. military has carried out airstrikes against al-Qaida fighters in different provinces of the war-torn Arab country since U.S President Donald Trump approved expanded military operations against the militant group.

The airstrikes included intensified overnight airstrikes and ground military raids against the al-Qaida hideouts in the mountainous areas of al-Bayda and southeastern province of Shabwa.

The Yemen-based al-Qaida branch, seen by the United States as the global terror network's most dangerous branch, has exploited years of deadly conflict between Yemen's government and Houthi rebels to expand its presence, especially in southeastern provinces.