Raiders killed villagers and burnt homes in an early morning attack in Kenya’s volatile coastal Tana Delta region that left 28 people dead, police said on Friday.

They said the raid appeared to have been a revenge attack following clashes between farmers from the Pokomo tribe and semi-nomadic Orma tribesmen, who have fought for years over access to grazing, farmland and water in the coastal region.

More than 100 people died in a series of attacks in the area earlier this year.

“About 150 Pokomo raiders attacked Kipao village which is inhabited by the Ormas early Friday, but the Ormas appeared to have been aware and were prepared. A confrontation ensued and as result 19 Ormas and 9 Pokomos were killed,” Robert Kitur, Coast Region deputy police chief, told reporters.