The head of the government of Sao Tome and Principe, Patrice Trovoada, spoke of "extrajudicial executions" after the "attempted" putsch carried out by assailants on the night of November 24 to 25 at the army headquarters.

"We had, from our point of view, an attempted coup. The Armed Forces stopped this attempt. After the end of the operation, hours later, there were what we believe to be extrajudicial executions, the execution of people who were key witnesses," he said in an interview with the Lusa agency broadcast on Wednesday.

"At the very least there was a lapse in command. The people under the responsibility of the Armed Forces cannot die, they are in detention," added Mr Trovoada, who moved Tuesday to Portugal, the former colonial power of Sao Tome, a small and very poor archipelago in the Gulf of Guinea, independent since 1975.

After a meeting with Portuguese President Marcelo Rebelo de Sousa, he said he expected his country's judicial authorities, assisted by Lisbon, to produce a "preliminary report" on the events he reported on November 25 before the end of the year.

On that day, Trovoada said that four assailants were captured after six hours of gunfire at the army headquarters in the capital Sao Tome and that two "sponsors" were later arrested at their homes, the former president of the outgoing National Assembly, Delfim Nevès, and another opponent, Arlécio Costa.

Two days later, the army chief of staff announced that three of the detainees had died from injuries sustained in an "explosion", without further details, and that Mr Costa had also died "jumping from a vehicle". But also, that 12 soldiers who "participated" in the attempted putsch had been arrested.

Many grey areas surround the circumstances and chronology of the events of Friday and the following days.

Opposition leader Delfim Nevès accused the government of having ordered the "coup attempt" and denounced a "sham" intended to "eliminate" him.

The government last week ordered an investigation into "cruel and inhuman acts" allegedly committed by the military against men accused by the Prime Minister of having attempted to carry out the "coup".