Five suspected bandits were shot dead during a fierce gun battle following an attack on a village in Marakwet East on Friday.
The armed cattle rustlers were shot dead in two separate incidents at Chesegon on the border of Elgeyo Marakwet and West Pokot counties.
Authorities said on Saturday that six people were injured during the renewed clashes in Kerio Valley.
Wilson Tangus, Marakwet East assistant deputy county commissioner, said the suspect Marakwet bandits crossed the border and stole an unknown number of cattle.
He said three West Pokot herders were killed during the shootout which followed after the herders sought to recover their stolen cows.
"Pokot herders launched a hot pursuit killing one Marakwet bandit and injuring three others during the gun fight at 12.30pm."
He said the Marakwet bandits managed to escape with the cows but were later ambushed by another group in Kapkobil village near Tot trading centre.
"At about 6pm, the Marakwet youth drove the cows away towards Marakwet but were accosted by a group of attackers from Baringo."
"We suspect that the West Pokot herders sought for reinforcement from their Baringo counterparts," Tangus said.
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"Police officers have been deployed on the ground to prevent further retaliatory attacks and to arrest those involved the fighting," he added.
Those injured in the fight were rushed to Iten county referral Hospital for treatment.
Locals said the area is still tense following the incident that happened months after calm returned in the troubled valley.
Wilson Kiptoo said the bandits, drawn from different villages in Marakwet East, stole at least 40 cows from a village in West Pokot.
The fresh attacks happened in the wake of peace meetings spearheaded by West Pokot Governor John Lonyangapuo and his Marakwet counterpart Alex Tolgos.
No banditry attack has been recorded in Kerio Valley since August 2017.