Several people were injured after panga-wielding youths clashed in Nairobi's Kawangware following differences over the presidential election.
Witnesses told The Star that the youths stormed the area on Friday and started attacking people randomly.
"I can see them from up here in this building, they are cutting people," a resident said.
Police said the retaliatory attacks followed after some trader's shops were looted on Thursday.
Dagoretti OCPD Rashid Mohamed said they have put a buffer zone to prevent both sides from attacking each other.
"Protesters looted shops and owners are now retaliating. It is serious but we are in control," he said.
Rashid said no deaths had been reported but noted that may people sustained serious injuries.
NASA had called for elections boycott and asked its supporters not to vote.
President Uhuru Kenyatta, on the other hand, urged his supporters to turn up in large numbers and vote for him.
