A senior Equatorial Guinea official has accused the former Spanish government of involvement in the plot to overthrow President Teodoro Obiang Nguema.
National security adviser Ruben Maya told the BBC that mercenaries involved in the plot said they had been backed by Spain's security services.
Opposition leader Severo Moto, in exile in Spain, is among those given long jail terms years over the plot.
Spain has previously denied similar accusations from Guinean officials.
In June, a presidential advisor said that a Spanish warship with 500 marines had been involved in the March attempt to topple President Teodoro Obiang Nguema, leader of the small, oil-rich nation.
UK statement welcomed
"All the threats Equatorial Guinea is facing come from Spain," Mr Maya told the BBC's Network Africa.
He stressed that it was the former government of Jose Maria Aznar, which lost March elections, which he was accusing of involvement.
"We hope that the [current] Spanish government will condemn the activities of the former government," he said.
British and South African mercenaries have also been sentenced over the plot - one group in Equatorial Guinea, another in Zimbabwe, where they tried to buy weapons on their way from South Africa.
Mr Maya said that men arrested in both countries had admitted that Spanish security and intelligence officials had supported them.
He also welcomed a "transparent" statement from UK Foreign Secretary Jack Straw following claims that the UK had advance warning about the coup plot but did not inform the Equatorial Guinea government.
He said this showed that western countries were aware of the plot.
Equatorial Guinea has accused several British businessmen, including Sir Mark Thatcher, son of the former UK Prime Minister Margaret Thatcher of funding the coup.
Sir Mark denies the charges.
His trial in South Africa has been delayed until April but in the meantime, he has been banned from leaving the Cape Town area.
Correspondents say the Equatorial Guinea court's decision not to impose the death penalty for the mercenary leader and Mr Moto could help it achieve the extradition of Sir Mark.