At least six people were killed when gunmen opened fire on two buses in Kenya near the Somali border Friday.
"Police on the scene have found six persons shot dead," police chief Joseph Boinnet said. "The hunt for the terrorists is under way."
Four civilians and two armed guards are believed to be among the victims. At least two more passengers were injured.
Similar attacks in the impoverished region of northeast Kenya have been carried out by al-Shabab, an Islamic militant group based in neighboring Somalia.
Just one day earlier, at least 20 people were killed in a massive roadside explosion that engulfed a passenger bus in Somalia.
Al-Qaida-linked al-Shabab has killed thousands of people since it began its campaign of terrorism 10 years ago to turn Somalia into a conservative Islamic state.
VOA's Harun Maruf contributed to this report.