By Njuwa Maina and Nicolo Gnecchi
MATHARE, Kenya, Jan 3 (Reuters) - Slum dwellers live in fear and eye each other with suspicion in the "Kosovo" district of Nairobi's Mathare slum, where men armed with machetes guard their homes and say they are ready for war.
Kenya has been convulsed by ethnic violence since President Mwai Kibaki's disputed re-election on Sunday, largely pitting Luo supporters of opposition candidate Raila Odinga against Kibaki's Kikuyu tribe and the police.
"Kibaki must step down! No Raila, no peace!" yelled Nixon Orua, sparks flying as he slashed his machete on a road amid the densely packed tin roofs of Kosovo, a shanty-town named after the violent and ethnically divided breakaway province of Serbia.
"We are ready to die."
Battle lines have been drawn as residents cower behind closed doors, fearing gangs drawn from the Kikuyu and Luo communities are plotting more attacks and counter strikes.
Locals say that for five days, police swept in sporadically and fired teargas and bullets in the air to disperse angry mobs.
But then they always departed, leaving the streets under the control of militants like the "Mungiki" gang, which has its roots in traditional Kikuyu rites, or the rival Luo "Taliban".
Mathare -- also known as "Unhappy Valley" in contrast to the "Happy Valley" of central Kenya once enjoyed by white settlers during British colonial rule -- has seen many of the clashes.
Houses lie in smouldering ruins and vigilante groups patrol its muddy, rubble-strewn streets.
Tensions exploded when Kibaki was declared victor in a vote Odinga's party said was rigged, and the violence pitted tribe against tribe and neighbour against neighbour.
"WHAT HAVE WE DONE?"
Some Kikuyu families sheltered in a police compound on the edge of Mathare after their homes were burned down.
"We all had one vote. I voted for one person and another voted for another. Now they say this vote has been stolen, but what have we done wrong to deserve this?" asked Joseph Mwangi, a Kikuyu tradesman whose house had been ransacked.
The tribal clashes in what had been seen as one of Africa's most stable democracies have shocked the world. They have flared from towns in the opposition's western heartland to tourist resorts on the Indian Ocean coast.
But Nairobi's sprawling, ethnically polarised slums have endured the most sustained bloodletting.
Opposition loyalists accuse the police of siding with local Kikuyus.
"Tribalism is with the government, not with us. I was attacked by Mungiki when I was coming from town because I am a Luo. I say this violence is political," said carpenter Pamba Odiango, bearing a crudely stitched gash across his face.
Many Mathare residents say the bloodshed is not just about ethnicity, but has also exposed fury over the huge disparities in wealth in the Kenyan capital -- where some of Africa's biggest slums sit near affluent homes, offices and shopping complexes.
"The fight in this country is not between the Kikuyus and the Luos. It is between the winners and the losers, the greedy and the needy," said local businessman Fred Oumuto.
"President Kibaki is the greediest man in this country."
Chege Kinyanjui, an 89-year-old Kikuyu, leant on a walking stick at the police compound where he fled with this family.
"I have never seen this hatred in Kenya. Tell me what is this for?" he demanded, waving his national ID card.
(Editing by Daniel Wallis and Giles Elgood)