NAIROBI (Reuters) - President Mwai Kibaki has beaten opposition leader Raila Odinga by a narrow margin to win re-election in Kenya's closest ever vote, the head of the Electoral Commission of Kenya (ECK) said on Sunday.

"The commission therefore declares Honourable Mwai Kibaki as the winner," ECK chairman Samuel Kivuitu told a small group of reporters at the election tally centre.

Kivuitu, whose attempt to make the announcement in public was halted by scuffles and shouting minutes earlier, said Kibaki had 4,584,721 votes compared to 4,352,993 for Odinga.

Odinga's opposition party has called the count a fraud.