Libreville: Gabon's army officers announced on Wednesday that they have taken power in the country and annulled the results of Saturday's presidential election in which President Ali Bongo was declared the winner.

Twelve soldiers appeared on national television, announcing they were cancelling the results of the election and dissolving "all the institutions of the republic," according to BBC.

The electoral commission said Bongo had won just under two-thirds of the votes in an election the opposition argued was fraudulent.

His overthrow would end his family's 53-year hold on power in Gabon.

The army officers also said the country's borders had been closed "until further notice." One of the soldiers said on TV channel Gabon 24: "We have decided to defend peace by putting an end to the current regime." This, he added, was down to "irresponsible, unpredictable governance resulting in a continuing deterioration in social cohesion that risks leading the country into chaos." There was no immediate response by the government to the soldiers' announcement.