Five knife-wielding men have attacked Galole Constituency tallying centre at Hola Secondary School in Tana River County.
The attackers stabbed one person to death and injured several others on Wednesday evening before police gunned down two of them.
Police sources said the victim is a student at Kenya Medical Training College.
Three of the attackers managed to escape on foot, according to Nation agent Stephen Oduor, who is among those stuck at the centre.
The attack disrupted vote tallying at the centre as IEBC officials, agents, candidates and their supporters stormed out of the station in fear.
Coast Police boss Larry Kieng confirmed the attack, saying police were pursuing the attackers who escaped.
"Two of them were killed. They were only armed with knives. We want to warn if the incident is politically motivated then the politicians there should know that we will deal with them" said Mr Kieng
He said police would not allow politicians "to misuse youth for their selfish interest".
" We understand that the tallying exercise is ongoing and if some leaders have sensed defeat and want to misuse the youth then they should know that we will deal them accordingly," said Mr Kieng.