Some 14 million Kenyans are eligible to vote in presidential and parliamentary elections in east Africa's biggest economy but many are braced for violent skirmishes in a race shaping up to be Kenya's closest ever.

"In Kuresoi, Molo area, police records indicate that 16 persons have been killed, 67 houses have been burnt and about 287 families have been displaced," police spokesman Eric Kiraithe told reporters.

Police have arrested 102 suspects, of which 60 have been charged and the others questioned and released, he said.

Kenya's President Mwai Kibaki is seeking a second five-year term in office and recent opinion polls have him running neck and neck with his main challenger, Raila Odinga.

With less then four weeks to go, campaigns have reached fever pitch and party primaries last month were marred by fighting as crowds set ballot boxes on fire and stoned party officials.

Previous campaigns in Kenya have been plagued by violence between rival supporters. Last month, weapons including clubs, machetes and bows and arrows were found in a government vehicle belonging to an assistant minister.

"Generally the law and order situation in the country has been comparatively calm. Although a few incidents have been reported, the electioneering process has taken off well," he said.

He warned politicians against fanning tribal animosities.

"If you as a politician have been aiding or abetting these clashes in any way, we are certainly going to catch up with you. We are not going to spare anybody," he said.

Kiraithe said police were investigating the murder of a parliamentary aspirant from western Kenya who was shot and killed in the capital Nairobi on Sunday.

He said they were treating the incident as murder, but warned against speculation that it was politically motivated.

"The Kenya police are taking every measure to protect every aspirant or politician who feels they are threatened in any way," he said.

In the Mount Elgon region where hundreds of people have died in fighting over land, Kiraithe said police were recruiting locals to serve as reserve officers to stop militia attacks.