Long queues of voters are waiting to cast their ballots, as Kenyans choose a president in an atmosphere marred by accusations of poll rigging.

President Mwai Kibaki is seeking a second term, in what is seen as the tightest election in Kenya's history.

"I have not even milked my cow because today we are putting our country first," said Mary Muthoni Gikiri as she waited to vote.

Kibaki faces his toughest challenge from his former ally, Raila Odinga.

Odinga has been the front-runner in opinion polls in recent weeks - yet his team has accused the president's side of dirty tricks.

'Rumours'

Correspondents say the final hours before polls were characterised by mud-slinging, with Odinga's supporters accusing the president of using state security agents to help rig the polls.

Three police officers were killed after the opposition alleged that they were carrying pre-marked ballot papers.

In response, the president issued a statement denying any such plans.

Chief EU election monitor Alexander Graf Lambsdorff said he had not received any evidence of rigging.

"So far this is at the level of rumours and allegations."

More than 14 million Kenyans are eligible to vote - they are also voting in parliamentary and local elections.

President Kibaki, running under the banner of a broad-based coalition known as the Party of National Unity, hopes his economic record will secure a second term.

Odinga, who heads the Orange Democratic Movement, played a key role in Kibaki's 2002 victory.

But the pair fell out soon afterwards.

Kibaki's critics accuse him of failing to keep his promise to tackle corruption.

There are eight candidates standing in the presidential elections.

PHOTO CAPTION 

A Kenyan man casts his vote. [AP]

BBC