TOM MALITI NAIROBI Political and ethnic loyalties have long been linked in Kenya. The violence that has erupted since President Mwai Kibaki claimed re-election shows how volatile the mix can be.

The lead-up to last week's vote was typical, with 39% of people interviewed by one polling agency saying they believed voters would base their choice on tribe, and candidates on the campaign trail using a mix of direct and indirect ethnic appeals.

Kibaki's Kikuyu comprise the largest ethnic group in Kenya, and are frequently accused by other tribes of monopolising business and political power.

Kenya has more than 40 tribes, among them the stately, cattle-herding Masai and the Kalenjin of the Rift Valley. In an attempt to force candidates to reach beyond their own tribes, Kenyan lawmakers amended the constitution in 1992 - the year multiparty politics were reintroduced after a long period of one-party rule.

Different provinces tend to be dominated by different tribes, so the amendment was aimed at ensuring a president has some support in most of the country.

Since some tribes are larger than others, a first-past-the-post system would usually mean members of larger tribes would win and not have to seek support of other tribes.

But in 1992, the new opposition parties campaigned primarily in their perceived tribal strongholds. .

That year, tribal clashes fanned by politics killed hundreds and forced hundreds of thousands of people to flee their homes. Many have been unable to return.