Suspected Al-Shabaab militants killed three Kenyan teachers and injured one other in an attack Friday on a school in the country’s northeastern county of Wajir, officials said.

The militants in early morning attacked the Qarsa primary school near the borders with Somalia and Ethiopia, in a town about 70 km from Wajir town, the capital of the county, killing three non-local teachers, said Mohamud Saleh, coordinator of Kenya’s northeastern region.

Authorities have been working to find another teacher who was allegedly shot in the hand and escaped with injuries.

Saleh said that ongoing efforts have been made to trace the killers, who escaped soon after the incident.