The country's caretaker government vowed to go ahead with Sunday's presidential election despite fears that President Mathieu Kerekou's troops will intervene if he loses.
Strikes and riots toppled Kerekou's Marxist military dictatorship a year ago, forcing him to agree to an interim government that would rule until presidential elections.But Kerekou has said at rallies for his supporters that he would "not leave if there is disorder" or fraud at the polls Sunday, prompting fear that he is plotting to derail the election by instigating unrest.
If Kerekou loses, he would be the first president on the African continent deposed by ballot.
The 13 candidates might split the vote, forcing a second round of balloting between the two top candidates on March 24 if no candidate wins a majority Sunday.
Benin's transition to democracy was peaceful until Kerekou surprised the nation of 5 million by announcing he would defend his presidency.
Marches to support Kerekou have turned into violent demonstrations that newspapers said were led by his 1,500-man Presidential Guard. Opposition supporters have been attacked and the offices of Kerekou's strongest rival, interim prime minister Nicephore Soglo, were ransacked.
Fear that Kerekou's troops will intervene in the election was fueled by the theft of ammunition and grenades from an army base where pamphlets signed by an unidentified "death squadron" threatened a coup to unseat the interim government.
But on Saturday the president said people had nothing to fear from his palace guard.