Suspected Somali-based al-Qaeda affiliated al-Shabaab militants killed eight people on a bus Friday in northern Kenya, according to authorities.

The militants attacked the 50-passanger bus headed from the Kenyan capital to Wajir County, killing only non-Muslims. Wajir in northern Kenya is predominantly inhabited by Muslims.

Wajir County Police Commander Stephen Ng’etich told reporters that “armed men ambushed a bus that was travelling to Mandera on Friday evening.”

He said militants separated non-locals from Wajir County residents and released the bus to proceed to Wajir, executing the remainder who were visiting the county.

Read more: 8 killed in bus attack in northeast Kenya