Eleven people were killed in a fierce gun battle between Borana and Samburu herders near Isiolo-Samburu border.
The fight took place in a grazing field in Kom, former Merti district, where herders from Isiolo, Samburu and parts of Marsabit had migrated to in search of water and pasture.
According to Isiolo County Commissioner George Natembeya, the remote area is about 200km North West of Isiolo town.
Isiolo County Police Commander Charles Ontita has said local Borana herders had earlier in the morning attacked their rivals at around 6am and stolen about 400 cattle.
"The Borana attacked the Samburu and stole the animals. The owners pursued them and caught up with them resulting in a fierce fight," said Mr Ontita.
He said six people from Isiolo were killed while the Samburu had four casualties.
At around 1pm yesterday, a hotelier at Archers Post, who hails from Isiolo town, was attacked with stones and clubs at his premises and killed in what sources said was a revenge attack.
Reports from the ground obtained from both sides including chiefs said both sides engaged each other for more than eight hours.
Ontita said a Samburu herder sustained gunshot wounds. A joint security personnel aided by an aircraft from Northern Rangeland Trust (NRT) recovered 380 of the stolen animals. 20 cattle were killed in crossfire.
Mr Natembeya said the Borana had last month refused to allow Samburu herders to graze in Kom.
"Both sides are heavily armed with illegal weapons and quick intervention of joint security personnel and the aircraft from NRT assisted us to recover most of the stolen animals and separate the warring sides," he said.
He added: "What is sad is that we lost many lives due to rivalry over grazing fields and cattle rustling."