"A bomb exploded in the car of Major Ahmed al-Harmali, the police chief in the town of Rawkab," east of Mukalla in Hadramawt province, said the official, adding that "he was killed along with two of his bodyguards."

"Four others sustained minor wounds," he said, requesting anonymity.

The official said the attack appeared to be the work of Al-Qaeda which is active in southern Yemen, although it was dealt severe blows this week after troops drove the jihadists out of three cities in neighbouring Abyan province.

"The Al-Qaeda organisation is very active in Hadramawt and is usually behind such attacks on police and intelligence officers," he said.