Angolan police on Saturday stopped a protest by a youth movement demanding answers over the disappearance of two of its members last year, the organisers said.
About 100 people had gathered for the protest before being dispersed by police.
The findings of an investigation into the two young activists, who went missing during a veterans protest last May, was meant to be made public last week.
"We will continue to push until they reappear or the truth is told," Adolfo Campos, one of the organisers of the aborted event told AFP.
Some demonstrators were arrested and equipment seized from journalists on the scene, said Joao Manuel, a young protester arrested and released by the police.
The president of a Angolan human rights organisation, Jose Patricinio, denounced the police action.
"It is sad to see the police use such violence against young people who are demonstrating peacefully," he said, adding that it was a constitutionally guaranteed right.