Fri Aug 27,11:50 AM ET

HARARE (AFP) - A court in Zimbabwe found the alleged British coup mastermind Simon Mann guilty of attempting to illegally buy arms to stage a putsch in oil-rich Equatorial Guinea but acquitted 66 other co- accused.

Mann, wearing a khaki prison shirt and shorts, showed no emotion as he stood before Magistrate Mishrod Guvamombe who read out the verdict at a makeshift court in the maximum security Chikurubi prison.

"The action by the accused (Mann) amounts at the most to attempting to purchase firearms. The accused is found guilty," said Guvamombe. He said sentences would be handed down on September 10.

Mann, a bespectacled former member of Britain's crack Special Air Service military unit was alleged to have been the mastermind behind the suspected plot to overthrow President Teodoro Obiang Nguema of Equatorial Guinea.

He was arrested along with 69 other alleged mercenaries on March 7 when a plane stopped off in Harare to pick up weapons that the men claim were to be used to guard a diamond mine in Democratic Republic of Congo (news - web sites).

The state has asked for a jail sentence of up to 10 years in prison for Mann, who is also linked to accused coup financier Mark Thatcher, the son of former British prime minister Margaret Thatcher.

Guvamombe acquitted 66 other suspected soldiers of fortune Friday, although most of them -- 64 -- and three crew members are still facing sentencing on minor charges of breaching the country's immigration and aviation laws.

Two other men described as weapons inspectors who were arrested along with Mann at the airport where they awaited the plane's arrival -- South Africans Harry Carlse and Jacobus Horne -- faced no charges and were to be released later in the day.

As the judge declared the acquittal of the 66 men, applause broke out from the small group of family members who attended the hearing.

There were tears and a flurry of excited calls on mobile phones outside the prison as relatives broke the news to family members back home in South Africa.

"I think it was a fantastic day," said Harry's brother Johnny Carlse. "This has been the best news in six months. I can't believe it."

Namibian Alexandra Ngombe said she was overcome with relief when she heard the verdict after having traveled to Zimbabwe ten times to visit her detained husband Kauhitwa Ngombe.

"It's been very stressful," said Ngombe, a mother of three. "I was worried, but now he's coming back home."

Guvamombe said the testimony by some of the men on how they were recruited in South Africa was "suspicious", but said the state had failed to link the men to the purchase of firearms.

Some of the men -- who included Angolan, Nambian and Congolese nationals travelling on South African passports -- said during the trial that they were recruited via telephone in South Africa to work as security guards.

"The manner in which they were recruited arouses some suspicion, however the suspicion alone is not enough," Guvamombe said.

"The state failed to discharge its onus by proving the accused persons guilty beyond reasonable doubt."

The prosecution has asked for jail terms of between one year to 18 months for violations of immigration offenses which 67 of the men, including the three-members crew, are facing.

Mann and Nick du Toit, a South African on trial in Equatorial Guinea in connection with the same coup plot, set up Executive Outcomes, which operated from Pretoria in South Africa and was active in Angola, Sierra Leone and Papua New Guinea.

The trial in Malabo opened on Monday with Du Toit admitting to a limited role in the plot, overseeing logistics.

The prosecution in Equatorial Guinea said it is seeking the death penalty for him.

The case took a new twist this week with the arrest in Cape Town of Mark Thatcher, who has been charged with bankrolling the alleged plot to topple the regime in Equatorial Guinea.

Thatcher has denied the charges but admitted that he is friends with Mann, who is his neighbour in the upscale Cape Town suburb of Constantia.