Iran's hard-line judiciary acknowledged for the first time Saturday that at least three prisoners detained after June's disputed presidential election were beaten to death by their jailers, confirming a key claim by the country's opposition movement. The surprising acknowledgment followed months of repeated denials by police and other authorities that the deaths of protesters in Iranian custody were caused by abuse. In a statement, the judiciary said 12 officials at Kahrizak prison were charged - three of them with murder. The prison, on the southern outskirts of the capital, Tehran, was at the center of the opposition's claims that prisoners were tortured and raped in custody. The claims embarrassed Iran's clerical rulers and forced Supreme Leader Ayatollah Ali Khamenei to order the closure of the facility. Police and judiciary officials had for months rejected the claims, saying the deaths were caused by illnesses, not physical mistreatment. Authorities fired back, accusing the opposition of running a campaign of lies against the ruling system. "The coroner's office has rejected that meningitis was the cause of the deaths and has confirmed the existence of signs of repeated beatings on the bodies and has declared that the wounds inflicted were the cause of the deaths," the Web site of Iran's state TV quoted the statement as saying. The opposition says at least 72 protesters were killed in the postelection crackdown, but the government puts the number of confirmed dead at 30. Iran's police chief, Gen. Ismail Ahmadi Moghaddam, said in August that protesters were beaten by their jailers at Kahrizak, but he maintained the deaths were not caused by the abuse. The opposition's criticism was implicitly aimed at the elite Revolutionary Guard, which operates with some autonomy from the ruling clerics and led the harsh crackdown and detention of protesters in the tense weeks after the election. The unrest broke out after Iran's opposition leader, Mir Hossein Mousavi, claimed he was robbed of the presidency through massive fraud in the vote.