UNITED NATIONS - Equatorial Guinea denied on Wednesday that it had abducted four former military officers it subsequently convicted of a coup attempt and executed last month, saying they had returned voluntarily to their country.

Amnesty International said last week the four had been living as refugees in Benin but were abducted in January and placed in secret detention before trial.

The human rights group said the government of Equatorial Guinea, an African oil-producing nation, had executed the men "with chilling speed" directly after an August 21 trial. It said the trial was unfair and lacked an appeals process.

Equatorial Guinea confirmed the executions on Friday.

Gunmen in motor boats tried to storm the palace of President Teodoro Obiang Nguema in February last year but were repelled by the armed forces.

At a news conference on Wednesday, Equatorial Guinea's U.N. Ambassador Anatolio Ndong Mba referred to reports that the four men had been abducted variously from Benin, Nigeria or Cameroon.