The victims included members of former president Laurent Gbagbo’s Ivorian Popular Front (FPI) who "have faced illegal detention and torture with many still languishing behind bars", Amnesty International said after a month-long mission to the West African country.
"We were able to meet dozens of detainees who told us how they have been tortured by electricity or had molten plastic poured on their bodies. Two of them have been sexually abused," said Gaetan Mootoo, Amnesty's researcher on West Africa.
"Some have been held for many months [and] denied contact with their families and access to lawyers."
In a first reaction, Human Rights Minister Gnenema Coulibaly said the president was "committed to fighting impunity".
Asked about arbitrary detentions, he told AFP that "when the security of the state is under threat the army will step in" before the police police and judicial officials get involved.
People who have been tortured should "contact the authorities with the evidence".
Gbagbo ruled Côte d'Ivoire from 2000 to 2010. He was forced from power after a disputed election escalated into clashes, which claimed some 3 000 lives before forces backing his rival Ouattara arrested him in April 2011.
Among those held illegally in the commercial capital Abidjan, "some have been charged with endangering the security of the State, others were released without charge or trial. In some cases release followed ransoms being paid to military officers," according to the statement.
"In many cases families have, despite tireless requests and efforts to trace relatives in different places of detention, been left with no information about their fate and only learnt of their whereabouts through Amnesty International."
The Amnesty team met high-ranking officials close to Gbagbo detained in four towns in central and northern Côte d'Ivoire, including Gbagbo's wife Simone who is held in the town of Odienne, his son Michel, held in Bouna, plus key figures from the toppled administration held in Boundiali and Korhogo.
All these people face charges including crimes against state security and murder.
"Some of them told us that despite the fact that they have been held since April 2011, they only saw an investigating judge [prosecutor] twice for less than a few hours," Mootoo said.
Amnesty also reported on an attack in July at a displaced persons' camp at Nahibly, near the town of Duekoue in western Côte d'Ivoire, which sheltered members of the Guere ethnic group, held to be pro-Gbagbo.
Official accounts said the attack claimed six lives, but six bodies were recovered in mid-October from a well, which were those of further victims, according to residents. An autopsy was carried out, but no details released.
Many witnesses spoke of arbitrary detentions, disappearances and extrajudicial executions after the attack carried out by Dozos, who are traditional hunters acting as a militia force backed by the state, according to Amnesty.
Ouattara's security forces have since August been subject to attacks by armed groups, blamed on Gbagbo supporters, but Amnesty warned against arbitrary arrests and detentions as a response.
"While acknowledging that the … government is facing a wave of attacks, we are very worried that the current arrests and repression stem from a willingness [for] reprisals and revenge," Mootoo said.
"More than 18 months after the arrest of Laurent Gbagbo in April 2011, it’s high time for President Alassane Dramane Ouattara to go beyond promises and put the respect of human rights at the top of his government’s agenda." – Sapa-AFP