Kainuk (Kenya) (AFP) - John Kelai became a runner to escape a hard and dangerous life in northern Kenya, where three of his uncles were killed in armed cattle raids when he was a teenager.Now the 38-year old top marathon runner has returned to lead a peace march, hoping to end cattle rustling and revenge killings in Kenya's remote and impoverished north."We must come out together and forget our differences, our tribal lines, and speak out in one voice: enough is enough," said Kelai, the 2010 Commonwealth champion.Rivalries between pastoralist communities competing for scarce resources, such as livestock and water, are worsened by easy access to automatic weapons and the absence of state security officers.Kelai is organising the 836-kilometre (520-mile) peace march, with Ethiopian running legend Haile Gebrselassie expected to join for the final stages of the walk, due to end on August 6.Shouting "Amani!