West Africa Correspondent Mark Doyle: "The authorities have put on a show of force for this election"

The authorities in the west African state have also closed land borders, airports and sea ports across the country.

The election is seen as a test for democracy in Guinea after decades of military rule.

President Lansana Conte is expected to be re-elected

Incumbent president Lansana Conte is widely expected to win his second five-year term of office.

The former army chief first took power in 1984 after the death of the Marxist dictator Sekou Toure.

Campaigning for the election has been marred by ethnic violence.

Over the weekend, the mainly ethnic Fulani supporters of one opposition presidential candidate, Mamadou Ba, clashed with the ethnic Soussou followers of President Conte.

'Rigging' accusation

Opposition candidates have also accused the electoral authorities of trying to rig the election in the president's favour.

They say the authorities have only distributed voting cards to the president's supporters.

Alpha Conde, presidential candidate for the Guinean People's Rally, said that only about 33% of voters had received voting cards in the areas he had visited.

Government officials initially denied voting cards were improperly distributed. They later said voters would not need the cards to take part in the poll.

Guinea has been struggling to introduce democracy after decades of military rule.

President Conte seized power in a coup before overseeing the establishment of multi-party politics in 1993.