Candidates

President Yahya Jammeh - Alliance for Patriotic Reorientation and Construction Ousainou Darboe - Three-party opposition alliance Sherriff Mustapha Dibba - National Convention Party Hamat Bah - National Reconstruction Party Sidia Jatta - People's Democratic Organisation for Independence and Socialism

The BBC's Mark Doyle says the atmosphere is so far peaceful despite a vigorous campaign marred by violence that left at least one opposition supporter dead.

He says the country is using a unique voting system in which each voter drops a marble into a drum for their preferred candidate.

"The marble strikes a bell inside the drum to ensure multiple voting can be detected", he said, adding that bicycles have also been banned from polling stations to prevent confusion with the ballot bells.

Five candidates are contesting the elections which observers have described as a test of President Yahya Jammeh's commitment to democratic reforms.

Closely run race

More than half a million voters are registered to vote in the election seen as the closest run race in the country's history.

Violence has been a theme of the campaign

It sees the current president, the leader of a military coup in 1994, being opposed by a civilian coalition opposed to any vestige of military rule.

The coalition is led by a lawyer, Ousainou Darboe.

Thursday's election is the first truly multi-party vote following the lifting in July of a ban on political parties which Mr Jammeh imposed soon after his coup.

Voters roll

However, a series of last-minute decisions by the electoral commision have created some confusion.

Police say they will crush anyone disrupting election

At first the commission said only people on the official final voters register could vote.

But then it reversed that decision and said those with a voter's card who appeared on a draft register, or "counterfoil" could cast a ballot.

Election officials have given conflicting accounts of what this means, and our correspondent says there are almost bound to be disputes about it.

Reuters news agency says the police on Wednesday evening issued a statement in which it made claims of a plot to disrupt the elections.

But, the statement went on: " The security forces are fully alert and will swiftly crush any act that threatens the peace and stability of the Gambia".

Correspondents say that following the campaign violence, which also saw an arson attack on the house of a ruling party MP, Gambians are praying that election day in this normally sleepy holiday resort remains peaceful.