An international watchdog group says a deadly shoot-out last month in Guinea was an "organized operation" planned in advance by the country's leadership.
Corinne Dufka is from the human rights advocacy group "Human Rights Watch," which has just finished a 10-day research mission in Guinea, interviewing victims and witnesses of last month's military crackdown.
She described the incident, in which security forces opened fire at a stadium in Conakry, killing unarmed anti-government protesters.
"The military, primarily the elite presidential guard, arrived in several different trucks, there were a few hundred of them," said Dufka. "They then deployed around the stadium and walked straight into the stadium in which you had tens of thousands of demonstrators gathered there in quite a joyous atmosphere and directly opened fire on them. They then after surrounding the stadium, blocked the entrances so as to make escape by the panicked individuals extremely difficult."
Human Rights Watch says more than 150 people were killed in the incident on September 28. But Guinea's government has put the death toll at 57. And it says most deaths were a result of crushing by the crowd and stray bullets.
But Dufka says the stadium attack was planned.
"You know it was not a spontaneous reaction to the protesters, it was something that clearly, you know, had been thought out and had the appearance of an organized operation," she said.
Dufka says her organization's research unearthed a high level of sexual violence during the crackdown. She says the group did not find any evidence that rape was ordered, but she says she believes permission for soldiers to commit rape was given.
"In no other time has there been this type of sexual violence, particularly out in the open," said Dufka. "There were a few cases of rapes, you know in houses and the neighborhoods, that is in previous years. But this time the sexual violence sort of erupted at the same time, simultaneously in numerous places within the stadium and then outside in the stadium grounds."
Dufka says a high level of intimidation against victims, witnesses, and human rights actors who are collecting evidence about the incident is taking place now.
"There was a cover up," she said. "There is very solid evidence that bodies were removed from the stadium, that bodies were removed from the morgue and buried in mass graves and the truth about what happened, the true human toll from this massacre must be revealed and those responsible must be held accountable."
The leader of Guinea's military junta, Captain Moussa Dadis Camara, seized power in a military coup last December.
Presidential elections are to take place in January. The African Union has said it will impose sanctions on the West African state if the coup leader is a candidate in the elections.
On Tuesday the European Union imposed an arms embargo on Guinea as a result of the September 28 crackdown.