© Reuters / Marko DjuricaA woman with a child casts her ballot inside a polling station in Kenya's town of Gatundu March 4, 2013.
A few hours before the 6 a.m. (0300 GMT) start of voting and with long queues across the nation, at least nine security officers in Kenya's restive coastal region were hacked to death, and six attackers were also killed, a regional police chief Aggrey Adoli said. The total toll had earlier been put at 17.
There were two separate attacks and senior police officers blamed one of them on a separatist movement - which, if confirmed, would suggest different motives to those that caused the post-2007 vote ethnic killings and could limit their impact.
Officials and candidates have made impassioned appeals to avoid a repeat of the tribal rampages that erupted five years ago when disputes over the poll result fuelled clashes between tribal loyalists of rival candidates.
More than 1,200 people were killed, shattering Kenya's reputation as one of Africa's most stable democracies and bringing its economy to a standstill.
As in 2007, the race has come down to a high-stakes head-to-head between two candidates, this time between Prime Minister Raila Odinga and Deputy Prime Minister Uhuru Kenyatta. Both will depend heavily on votes from tribal loyalists.
