SEOUL, July 30 (UPI) -- Former South Korean President Yoon Suk-yeol is being held in solitary confinement under conditions that have prompted concern from his legal adviser. According to his mentor, Shin Pyung, who recently visited him at the Seoul Detention Center, Yoon's treatment is "unfit for a human being" and may constitute a violation of both domestic and international human rights standards. Yoon is confined in 71-square-foot cell with no desk or chair. Instead, he sits on a makeshift cardboard platform, using it to eat meals and read the Bible -- which, according to his attorney, has become his only means of intellectual engagement during confinement. He eats meals while squatting, and his physical movement is limited to brief periods of outdoor exercise -- in isolation. Shin, who was granted access under attorney-client privilege, described the environment as "hell on Earth," noting that the former president lies flat on the floor at night without space to stretch. Despite evident physical discomfort and digestive issues, Yoon was said to maintain a calm and composed demeanor during the visit, even offering a faint smile when asked how he was doing. Claims of political retribution Shin condemned the conditions as politically motivated and accused the current administration of engaging in retributive justice. He further appealed to the international community to recognize the situation as an "uncivilized and barbaric act," urging diplomatic pressure from democratic allies to ensure humane treatment. The harsh conditions have sparked debate about whether South Korea is upholding its constitutional principle of equal dignity for all citizens -- including former heads of state -- while also observing international norms on the treatment of detainees. South Korea's Ministry of Justice has defended the detention center's actions, saying that Yoon is being treated like any other inmate under remand. Authorities said he has access to a fan for cooling during the summer heat, but denied that he is receiving any special accommodations due to his former status. The ministry also clarified that solitary confinement is standard for high-profile detainees during the investigative phase, primarily to prevent contact with other inmates and reduce the risk of evidence tampering. Comparisons with former presidents Critics note that previous presidents charged with criminal offenses, such as Park Geun-hye and Lee Myung-bak, were confined under significantly less austere conditions. Park was given a converted cell with more space and access to reading materials, while Lee was allowed to use a private bathroom and had access to a separate visitation room. Further back, former presidents Chun Doo-hwan and Roh Tae-woo were housed in specially constructed annexes with separate facilities, designed to respect the dignity of their former office.