Updated

After securing the conviction of the alleged lead mercenary in a foiled coup attempt, African prosecutors are turning attention to a widening web of British financiers accused of bankrolling the uprising in this tiny oil-rich nation in West Africa.

Equatorial Guinea has requested international arrest warrants for Mark Thatcher (search), son of the former British prime minister, and other Britons suspected in the plot, the country's deputy prime minister, Ricardo Mangue Obama Nfube, said Saturday.

The issuing of a warrant is necessary before formal extradition can be sought. Nfube said Equatorian Guinea (search) still was "studying" whether to seek the extradition of Thatcher, who was arrested on Wednesday in South Africa. There was no immediate word from Interpol, the international police agency that issues such warrants, whether it had received the request.

Spanning from London to Cape Town, South Africa, the alleged conspiracy was foiled in early March when security forces in Zimbabwe and Equatorial Guinea arrested Briton Simon Mann and 89 other alleged mercenaries as they allegedly prepared at airports in both countries to launch the coup plot.

On Friday, Mann — a former Etonian, British Special Forces operative, a longtime mercenary and a friend of Thatcher — was convicted by a court in Zimbabwe of trying to illegally buy weapons from that country's state arms manufacturer. Sixty-six other suspected mercenaries were acquitted by a Zimbabwe court the same day.

Prosecutors made no immediate reference to the arms, but government lawyers said they were among those to be used to oust Equatorial Guinea's President Teodoro Obiang Nguema (search), the 25-year ruler of the isolated, repressive West African nation of 500,000.

In Equatorial Guinea, shackled and handcuffed defendants Friday testified before a judges' bench obscured by machine guns, mortars and black military uniforms.

Equatorial Guinea says top British financial figures — including Thatcher, son of Margaret Thatcher (search) — conspired with a Spanish opposition figure and mercenaries from Britain, South Africa and other European and African nations.

The alleged aim: taking control of Africa's No. 3 oil producer, pumping 350,000 barrels a day in a boom that has given this backwater the world's fastest economic development growth.

"If Equatorial Guinea were a poor country, I don't think people would be attempting this kind of plan," Attorney General Jose Olo Obono told reporters on Friday.

Equatorial Guinea's government lawyers said they wanted to extradite Mark Thatcher, now under house arrest in Cape Town, South Africa, in connection with the plot. South African security forces arrested Thatcher, still in his pajamas, in a pre-dawn raid on his home there Wednesday.

Obono said Equatorial Guinea also may pursue extradition of other British financiers cited in testimony here as conspirators. "All of them," Obono said.

Financiers mentioned in court here include Eli Calil, a wealthy Briton of Lebanese origin whose deals include African oil investment, and British businessman Greg Wales. British newspapers also have cited bank records allegedly documenting $133,000 that disgraced British peer Lord Archer — the novelist Jeffrey Archer (search) — paid into a bank account held by Mann.

Lawyers for all the Britons have denied all the allegations. "Very good fun, but 'unadjacent' to the truth," The Guardian, a British daily, quoted Wales as saying of the accusations against him.

Equatorial Guinea's key witness is South African arms dealer Nick du Toit, accused of leading an advance team to line up men, aircraft and other vessels for the plot.

Prosecutors are seeking the death penalty against du Toit. One additional accused plotter, a German aircraft contractor, died in custody here after what Amnesty International said was torture.

South Africa and Equatorial Guinea have no joint extradition treaty.

If South Africa receives a request for Thatcher's extradition, a magistrate's court would rule on whether Thatcher was liable for extradition under South African law.

A spokesman for South Africa's national prosecuting authority said a successful outcome was unlikely given that Equatorial Guinea practices the death penalty.

"South Africa is opposed to the death penalty, and we wouldn't extradite someone to a country where he would face the danger of the death penalty," Makhosini Nkosi said, according to the South African Press Association.

Mann, admitted trying to order assault rifles, grenades, anti-tank rocket launchers and other weapons from the Zimbabwe Defense Industries — an offense punishable by up to 10 years in prison. However, he said the weapons were intended for security guards at a mining operation in the Congo.

Thatcher's spokesman Lord Bell told British Broadcasting Corp. radio that Thatcher's name had been dragged into the Equatorial Guinea affair because of "guilt by association."

"Mark Thatcher and Simon Mann were friends, nobody has ever denied that," Bell explained. "But it doesn't follow that because you are friends with someone you are necessarily involved in what they are doing."

Thatcher was scrutinized by Britain's Parliament in 1994 over reports that he was involved in arms sales to Saudi Arabia and Iraq while his mother was prime minister. He moved his family to South Africa in 1995 after business troubles in the United States. Trial here recessed until Monday, with no clear date for when verdicts could be expected.