At least 15 killed On Kenya Coast on Election Day

(Reuters) - At least 15 people were killed in attacks by machete-wielding gangs on Monday as Kenyans lined up to vote in a presidential election they hope will rebuild the nation's image after a disputed 2007 poll unleashed weeks of tribal bloodshed.

Just hours before the start of voting and with long lines across the east African country, at least nine security officers in Kenya's restive coastal region were hacked to death, and six attackers were also killed, regional police chief Aggrey Adoli said. The total toll had earlier been put at 17.

There were two separate attacks which senior police officers blamed 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.