Cedric Bao, a 33-year-old who was held for two weeks in August on suspicion of hiding weapons, said soldiers also attached wires to detainees and administered electrical shocks as they writhed on the ground.
"When that happened, the wires would produce a lot of noise, and the lights would flicker, and it would smell like burning. We could hear the people shouting," Bao said. "I was always praying to God not to be brought downstairs."
Ivory Coast's military has launched a widespread campaign of arrests and detentions, charge former detainees and human rights groups. Scores of Ivorians like Bao are being rounded up on allegations of involvement in recent attacks on the military or of otherwise attempting to undermine state security.
Since early August, Ivory Coast's military has been targeted in nine attacks by shadowy gunmen that have sparked fears of renewed violence in this West African nation, the world's largest cocoa producer.
President Alassane Ouattara's government has blamed the attacks on allies of former President Laurent Gbagbo, whose refusal to concede defeat in the November 2010 election sparked six months of violence that claimed at least 3,000 lives.
The country's U.N. mission said in mid-August that 100 arrests of those suspected of the attacks had been documented. A U.N. official, who is not authorized to speak for the mission, said this week that that number had more than doubled.
While torture allegations have been documented at multiple military facilities, the U.N. officials said that some of the worst came from detainees at the San Pedro camp, including credible reports of electrical shocks.
Few detainees in the city had spoken up about their experiences at the camp because of threats they received before being released, said Serges Dagbo, San Pedro representative for the Ivorian Human Rights League.
But in recent interviews with The Associated Press, four former detainees described harsh conditions marked by cramped quarters, minimal food and the frequent use of violence to extract confessions.
Like other detainees, 40-year-old Plika Sokouli said he was never told exactly why he was arrested in late August at the stand where he sells pineapples and homemade liquor.
But he said the threat of violence was apparent as soon as he arrived at the camp.
"When I got there a guard took a pistol and put it in my mouth and told me to speak," he said. "I said I knew nothing."
Christian Hino, a 34-year-old former gas station attendant who is currently jobless, said eight detainees were handcuffed before being subjected to one-on-one torture sessions, which lasted up to 25 minutes.
Of those, he said, four were laid down on the grass outside the camp's main building, and long wires were attached to their feet, midsections and necks before electrical shocks were administered.
"At around 4 a.m., a policeman who was arrested became unconscious from the electrocution," Hino said. "I was really afraid. He was not reacting. People were wondering if he was dead."
The camp's top official, Capt. Sekou Bema Ouattara, denied allegations of physical abuse, and claimed prisoners had never been held there for longer than a day or so.
Still, he defended the military's campaign to root out enemies of the state among the local population.
"It's because of our determination and work that San Pedro has not been attacked," he said.
Lt. Aboubakar Traore, the camp's second-in-command, also denied that physical abuse occurred at the camp. But he said soldiers may have resorted to torture while commanders were away.
"I don't want to say that we are perfect," he said. "I'm not sleeping here. I don't know exactly what the soldiers do when I'm sleeping."
But a guard at the facility, who spoke on condition of anonymity for fear of reprisals, said prisoners were routinely held there for multiple days for investigation. He also said beatings were commonplace, claiming they occurred when commanders were gone.
Asked whether the beatings were severe, he laughed and said: "There's no two ways of beating someone. We beat them severely so they can remember."
Abuse allegations in San Pedro should be investigated immediately, said Matt Wells, West Africa researcher for Human Rights Watch.
"The nature and pattern of the detainee mistreatment would indicate that, at a minimum, the camp's commanders should have been aware of such abuses and taken steps to prevent them and to punish soldiers involved," he said. "Ivorian authorities should investigate immediately and ensure that anyone responsible is brought to justice."
Meanwhile, there are concerns that the torture in San Pedro could soon worsen.
The government confirmed this week that Ousmane Coulibaly, a former zone commander in the New Forces rebel group, which controlled northern Ivory Coast from 2002 to 2010, had been appointed prefect of the San Pedro region.
Coulibaly has been implicated by Human Rights Watch in grave crimes during the post-election crisis, including torture and extrajudicial killings in Abidjan's Yopougon district.
Wells said the appointment "mocks the victims of these abuses and the government's promise to deliver impartial justice."
As they wait for Coulibaly to be installed in his new position, the former detainees in San Pedro question whether the abuse they and others have endured has made the city any safer.
"For me, I don't believe in the confessions they received," Bao said, "because these confessions were made under torture."