Somalia's al-Shabab Islamic extremists say they killed four people in Kenya's volatile northern region, bringing the total number of those killed by the militants since Friday to 12.

Kenyan officials said Wednesday that four people were shot dead in a shop Wajir town on Tuesday night by unknown gunmen who wounded three others. Kenyan Interior Minister Joseph Nkaisserry said the motive is unclear and the attackers are not known. But al-Shabab through its radio station in Somalia claimed responsibility for the attack.

On Sunday four people believed to be non-Muslims were killed in an attack by gunmen suspected to be al-Shabab militants in Mandera town. On Friday the militants claimed responsibility for attacking the convoy of Mandera County Governor Ali Roba in which four people died.