One person was shot and wounded Saturday morning after unknown assailants opened gunfire on a Kenya Red Cross vehicle in Ruqa, Garissa County.
Three others escaped unhurt.
Kenya Red Cross Secretary-General Abbas Gullet said in statement that the KRCS teams were travelling to Ijara from Masalani to conduct assessments on projects that the humanitarian organisation is implementing in the area when the attackers, from a nearby bush, shot at the vehicle from the front and the sides.
The injured volunteer was taken to Masalani Sub-County Hospital for first aid and was evacuated to Malindi by road for further treatment.
Mr Gullet said the rest of the team members received counselling and physiological support.
The incident was reported to police for investigations and a meeting was scheduled with leaders in the area, Mr Gullet said.
Ruqa and Ijara areas are near the vast Boni Forest where Al-Shabaab militants hide after targeting citizens and security personnel.
Two months ago, two people were beheaded after they were isolated from the rest of the passengers in a bus in Garissa.