Lansana Conte, the president, declared a state of siege on Monday and the army has said it will only end when trade unions agree to lift a crippling general strike.
The League of Human Rights says at least 64 people have been killed in clashes with the security forces since Saturday.
"Under the guise of reestablishing law and order, they're acting like common criminals, beating, robbing and brutalizing the population they're supposed to protect," he added.
Former colonial power France, hosting a summit of African leaders in Cannes, led calls for Conte's government to seek a peaceful political deal acceptable to all sides.
Chirac said French aeroplanes and ships were ready to evacuate, if necessary, about 2,000 French citizens from Guinea, as well as Lebanese, US and other citizens.
Guinean officials sought to fend off the criticism, saying security forces had faced looters, escaped prisoners and protesters who had obtained arms smuggled into the country.
|Rabiatou Serah Diallo, left, has demanded |
the president lift martial law [AFP]
It cited other sources as saying at least three women had been raped by uniformed personnel, including soldiers.
Camara told the Associated Press news agency that a commission had been formed to look into the allegations of abuse but warned that the unions must reach an agreement with the government before martial law would be lifted.
"The state of siege will never be lifted before negotiations find a solution," but could be "re-examined if there's a change in people's behaviour," he said.
The two sides are planning to meet on Saturday after they failed to reach a deal on Thursday.
Rabiatou Serah Diallo, a union leader, had demanded that Conte lift martial law to stop the suffering of Guinea's people. She said she was not asking for Conte to step down, but to honour his agreement and name a new prime minister, Mohamed Cheikh, deputy spokesman for the majority party in the national assembly, said.
Guinean authorities have eased restrictions at the country's main bauxite mine, Sangaredi, on Friday to allow a restart of halted exports of bauxite, the economic lifeblood of the country.