At least 157 people were killed when Guinean troops opened fire on opposition protesters on Monday, a human rights group says.
Earlier police said 87 people had died, but local activists say hospital sources confirmed a much higher toll.
Human rights groups say they have had reports of soldiers bayoneting people and women being stripped and raped in the streets during the protest.
Junta head Capt Moussa Dadis Camara denied knowledge of sexual assaults.
But he admitted that some of his security forces had lost control.
French Foreign Minister Bernard Kouchner said France was suspending military ties with Guinea after the "savage and bloody" crackdown on opposition protesters, the French news agency AFP reported.
Out of control
About 50,000 people were protesting over rumours that Capt Camara intends to run for president in an election scheduled for next January.
But soldiers moved in to quell the rally using tear gas and baton charges and firing live ammunition into the crowds.
The Guinean Organisation for Defence of Human Rights put the toll at 157 people killed and more than 1,200 wounded, although this has not been corroborated.
The opposition has accused the army of taking away some bodies to hide the scale of the violence.
Human rights groups said there were widespread reports of rape.
"The military is going into districts, looting goods and raping women," Mamadi Kaba, the head of the Guinean branch of the African Encounter for the Defence of Human Rights (RADDHO), told AFP.
"We have similar reports from several sources, including police sources and some close to the military," said Mr Kaba, from his office in Dakar, Senegal.
An eyewitness told Human Rights Watch: "I saw several women stripped and then put inside the military trucks and taken away. I don't know what happened to them."
"They were raping women publicly," opposition activist Mouctar Diallon said in an interview with French radio station RFI, adding that he had witnessed soldiers raping women with rifle butts during Monday's protests.
Guinean human rights activist Souleymane Bah told Reuters news agency that people trying to escape from the shooting were "caught and finished off with bayonets".
A doctor at a government hospital in Conakry said his wards looked like "a butchery".
Threat of sanctions
The BBC's Alhassan Sillah in Conakry says Capt Camara acknowledged that "uncontrollable soldiers" were responsible, but did not say how many people had died.
BBC


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