Islamist militant group Al-Shabaab has claimed responsibility for a bus attack that killed 28 people in Northern Kenya this morning, CNN reports. According to Reuters, gunmen separated passengers into groups of Muslims and suspected non-Muslims, sparing those who could recite the Koran.

"The Mujahideen successfully carried out an operation near Mandera early this morning," said an Al-Shabaab spokesperson in a statement,"which resulted in the perishing of 28 crusaders, as a revenge for the crimes committed by the Kenyan crusaders against our Muslim brethren in Mombasa."

Since 2011, forces from Kenya—a Christian majority country—have battled Al-Shabaab insurgents in Somalia. Last September, the Al Qaeda-affiliated group retaliated by killing 67 at Nairobi's Westgate mall.

[Image via AP Images]