A renowned Angolan journalist has been put on trial on charges of defaming military generals after he accused them of links to the “blood diamond” trade.
Rafael Marques de Morais accused seven generals of being linked to murder, torture and land grabs in Angola’s lucrative diamond fields.
Several people were reportedly arrested for protesting against the trial.
Mr de Morais is a long-standing critic of President Jose Eduardo dos Santos’ 35-year rule in Angola.
He spent 43 days in prison, including 11 in solitary confinement, in 1999 after he published the article, The Lipstick of the Dictatorship, in a private Angolan newspaper.
Dissent is generally not tolerated in Angola and some critics of the authorities are either bought off, jailed or disappear, says BBC Africa analyst Mary Harper.
The latest case against Mr de Morais comes after he wrote a book, Blood Diamonds: Torture and Corruption in Angola.
“There is no link between the Angolan armed forces and the crimes exposed,” Joao Manuel, a lawyer for the generals, is quoted by the AFP news agency as saying.
Judge Adriano Cerveira told the packed courtroom in the capital, Luanda, that the trial would be held behind closed doors, the reports.
Outside court, scuffles broke out between police and protesters who chanted “free Rafael” and “imprison the generals”, the agency said.
Speaking after the case was adjourned until 23 April, Mr de Morais said: “I went to court today facing nine charges of criminal defamation. I left slapped with up to 15 additional ones for defamation.”
Mr de Morais was in the UK last week to receive a freedom of expression award given to him by campaign group Index on Censorship.
It called for the charges against him to be dropped.
Before the trial opened, Mr de Morais told the BBC’s Focus on Africa radio programme that Angola’s leaders lead Western lifestyles with luxury homes and cars, but denounce critics as “stooges of imperialists” when they demand freedoms enjoyed by people in the West.
“As a good guy I’m out to fight these bad guys until I win,” he said.
If found guilty he could be sentenced to up to nine years in prison and fined $1.2m (£800,000).
The unregulated diamond trade fuelled Angola’s 27-year civil war, which ended in 2002.
Since the end of the conflict, the country – one of Africa’s major oil producers – has witnessed an economic boom, though critics of the elected government say the wealth has only benefited a small elite.