NAIROBI - Kenyan Prime Minister Raila Odinga will not concede this week's election and will launch a legal challenge if rival Uhuru Kenyatta is officially declared president, an adviser said on today.

Provisional results released in the early hours of Saturday handed Kenyatta a slim outright win with 50.03 percent of the vote. But Odinga's camp had said during tallying that the ballot count was deeply flawed and had called for it to be halted.

"He is not conceding the election. If Uhuru Kenyatta is announced president-elect then he will move to the courts immediately," said Salim Lone, a close adviser to Odinga.

In winning more than half the total votes cast, Kenyatta, who faces international charges of crimes against humanity, avoided a run-off after a race that has divided the East African nation.

The provisional results handed Odinga 43.28 percent of the presidential vote. Odinga also lost in a disputed vote in 2007 that led to weeks of tribal violence that killed more than 1,200 people.