GARISSA : Unknown gunmen shot dead an officer with a paramilitary security unit in northeasternKenyaon Saturday evening, police said.

The officer, Mohamed Mohamud, was ambushed in the town ofWajiras he was returning home after watching the evening news in a nearby restaurant, local police chief James Mutungi told AFP. He said the assailants' motive was not clear.

"These are people who knew him very well and decided to trail him. Our preliminary investigations show that the attackers committed the act from inside a taxi before speeding off," said Mutungi.

Wajir and other towns in east and northeastKenyahave been the scene of numerous attacks - often targeting the security forces - sinceKenyasent troops into neighbouringSomaliain late 2011.

The attacks are often attributed to sympathisers ofSomalia's Shebab fighters.