"They made a brutal incursion," said the witness, a close relative of former president Thomas Boni Yayi, who had led calls for a boycott of the ballot and whose house has become a focal point of protests.

"They fired bursts of bullets."

The witness said that three people were killed and that other protesters fled as soldiers open fire to disperse the crowds.

A video seen by AFP showed soldiers firing as protestors fled the gunfire.

The images showed some protesters lying on the ground, but it was not immediately possible to verify if they had been shot.

Large numbers of soldiers and riot police have been on the streets of Benin's economic capital Cotonou since Wednesday, hours after initial results showed a record low turnout in Sunday's election, in which no opposition candidates could take part.

Protestors erected makeshift barriers of burning tyres, and chanted slogans against President Patrice Talon.

They also torched businesses, hurled stones, and smashed the windows of government buildings. Police fired tear gas to break up crowds, and protestors tried to throw some canisters back.

A woman died on Thursday after being wounded the day before, medical sources said, and a man was brought to hospital with a gunshot wound in his back.

Violence was also reported in the town of Kandi, some 620 kilometres (385 miles) to the north, where one of the country's largest cotton factories -- a sector in which President Talon made his fortune before embarking on politics -- was set on fire.

The small West African state transited to democracy in 1990.

Its vibrant political scene has caused the country to be held up as a model, but rights groups say there is now a major risk of a return to authoritarianism.