The Luos is Kenya's third largest, with 13 percent of the population.

NPR: A Kenyan in the U.S. Helps His Family Escape

Kenya's 4m or so Luos, most of them in Nyanza, voted overwhelmingly for Mr Odinga in the disputed election on December 27th.

ECONOMIST: Kenya

Some Kenyans say ethnicity won't matter to them next week, but the polling also shows that almost all of the Luos are voting for Odinga and most Kikuyus are voting for Kibaki.

NPR: Kenya's Upcoming Elections Bring Ethnic Tension