(Updates with colonel killed in separate attack)
SANAA, Jan 16 (Reuters) - Suspected al Qaeda-linked militants attacked an army base in Yemen on Thursday, triggering clashes that killed nine soldiers and retaliatory strikes from the air force, a local government official and witnesses said.
Explosions rang out around the camp in the city of Radda, more than 100 km (60 miles) south of the capital Sanaa, witnesses told Reuters.
Yemen, which sits next to the world's top oil exporter Saudi Arabia and key shipping lanes, is home to one of al Qaeda's most active wings.
Islamist militants took advantage of chaos surrounding a popular uprising in 2011 to strengthen their hold on some southern areas, piling pressure on a government already facing northern rebels, southern secessionists and an economic crisis.
The insurgents were beaten back by the army but have since regrouped, mounting regular attacks on government officials and installations.
On Thursday, militants managed to get into the army camp and seized three army vehicles, said the official and witnesses, who asked not to be named.
The attack may have been in retaliation for an earlier, as yet unexplained explosion in the area that killed two militants on a motorbike, they added.
In a separate incident in southern Yemen, unidentified gunmen in a car ambushed and killed a colonel in the country's domestic security services who was returning home from work in the city of al-Buraiqa near the southern port city of Aden.
It was the latest in a long string of militant attacks targeting senior security and army officers, mainly in southern Yemen, since last year. (Reporting by Mohammed Ghobari, Writing by Sylvia Westall; Editing by Sami Aboudi and Raissa Kasolowsky)