CAIRO (Reuters) - Murad Ali says he was put in a foul-smelling cell on death row, sleeping on a concrete floor, and denied light and human contact after his arrest in Egypt's crackdown on the Muslim Brotherhood. "It was as dark as a grave," he wrote in a letter addressed to friends and family and seen by Reuters.
The army-backed authorities deny claims Brotherhood leaders have been mistreated, and there is no way to independently verify such accounts; but people who have spoken to them in jail say some have been kept in similar conditions for days on end.
Their relatives describe it as a bid to break their spirit - a measure of the severity of the campaign against the group that was swept from power by the military on July 3, when Mohamed Mursi, a Brotherhood member, was deposed.
Analysts say it points to a state effort to weaken the Brotherhood by decapitating it. The movement says it has up to one million members and it is one of the most influential Islamist groups in the Middle East.
"They are putting them under psychological pressure to break them," said a relative of another inmate, adding that in the first 13 days of his incarceration he had been let out of his cell only for questioning. "He said: ‘It is a grave. We are in graves'," she said. "It was as if he hadn't seen us for years."
The woman, like others interviewed, declined to be named for fear it would lead to tougher treatment in prison or retribution against her family.
The authorities have arrested at least 3,000 people since Mursi was toppled, according to Amnesty International. A state of Emergency gives security forces sweeping powers, though Brotherhood leaders have been detained under normal criminal laws. Much of Egypt remains under a nighttime curfew.
Accounts emerging from prisons indicate much tougher jail conditions for the leaders than the group faced under autocrat Hosni Mubarak, toppled in a 2011 revolt. Brotherhood leaders were generally treated better than most inmates in his day, for all the repression across the country at large.
But the group that propelled Mursi to power in Egypt's first freely contested presidential vote faces the toughest clampdown since the death of President Gamal Abdel Nasser in 1970.
While the Interior Ministry denied the leaders have been put in solitary confinement, it confirmed they had been separated for security reasons. Hany Abdel Latif, spokesman for the ministry, said prison rules allowing for exercise, medical treatment and library access applied to all prisoners.
"The situation is normal," he said.
Leaders of the Brotherhood, described by local media in terms akin to al Qaeda, have been charged with crimes including inciting violence and murder since the army deposed Mursi after mass protests against his rule.
Some of the leaders now seem to have no idea what is going on outside prison. A relative of one said he had been surprised to hear there were still protests against the army-backed government.
Amnesty International, citing Brotherhood lawyers, said Murad Ali's eyesight had been affected by the lack of light in his solitary cell. "He was also not allowed to take medication for blood pressure for two days," its Egypt researcher, Mohamed El Messiry, said. "Amnesty International is not able to confirm other reported cases," he added.
In a hand-written note Ali, arrested at the airport last month as he tried to leave the country, said his cell had no running water for the first two days. Charges against him include forming a "terrorist gang".
Spokesman for the Brotherhood's political party, he said the shutter in his cell door was kept closed for the first eight days.
Echoing Ali's account, two other senior Brotherhood politicians told state prosecutors they were being held in solitary confinement, official documents published by a local newspaper showed on Saturday.
Mohamed el-Beltagi, one of the two, said he had been held in a cell with no light or ventilation and had only been let out for questioning, according to the document, published on Saturday in Al-Masry Al-Youm, an anti-Brotherhood daily.
"I am not being dealt with as someone in pretrial detention," Beltagi said. "I have been dealt with in a political way in revenge for my politics."
Beltagi, charged with inciting killing and torture, also said he had been assaulted upon his arrival at prison, though the prosecutor reported no sign of injury in the document.
He complained that food and medication were not allowed - echoing complaints of relatives who say they have not been allowed to deliver food.
At least five prominent detainees have been held for days on end in poorly lit and ventilated cells with little or no human contact, according to written accounts attributed to some of them and interviews with relatives who had visited others. One of the relatives said she knew of at least a dozen such cases.
The police continue to arrest Brotherhood activists, a sign of how dim the prospects are of reconciliation with the army-backed government. Mursi is among those charged with inciting killing. His whereabouts remain a secret.
Security forces have killed at least 900 of his supporters in the streets since his downfall, the worst spasm of violence in Egypt's modern history. More than a hundred members of the security forces have also been killed since August 14, when the police moved to break up pro-Mursi sit-ins in Cairo.
"We can't compare it to Nasser - they were torturing and killing them (in prison) - but it is definitely worse than Mubarak," said Khalil al-Anani, an expert on the Brotherhood and a senior fellow at the Middle East Institute in Washington.
"Under Mubarak, they had access to the movement. There were connections between the leaders and organization, and they used to run the organization from prison. Now they want to make sure there is no connection, in order to break the Brotherhood and to push them to accept any deal," he said.
The leaders are being held at Tora Prison, a high security facility on Cairo's southern outskirts.
One relative noted that the prison authorities appeared to get tougher on the Brotherhood leadership a few weeks ago, when they stopped a group of them from eating together.
They were then confined to cells until medics warned that a lack of exposure to sunlight risked exacerbating skin diseases that some were already showing signs of, said the relative.
Murad Ali's letter says he was put in solitary confinement in a cell with no bed on August 22. The note says the lack of water for the first two days meant he could neither perform ritual ablutions nor clean the excrement he had found inside.
Eight days into his incarceration, the opening of the shutter in the cell door marked a "big step". It let in more air and light and allowed him to communicate with others, he wrote.
Twelve days into his detention he was let out for half an hour of exercise - something he is still permitted on a daily basis, according to someone who visited him.
Gamal Eid, a human rights activist, said that Brotherhood leaders, suspicious of Egyptian human rights activists they believe supported Mursi's overthrow, had turned down offers from activists who had sought to attend prosecutor questioning.
That questioning is being carried out in the prisons - something Eid described as a breach of human rights but which other Egyptian rights activists have said is understandable given security concerns.
Anani said many Egyptian human rights organizations had taken political positions against the Brotherhood, giving the authorities "carte blanche" to do as they please.
"They used to receive a middle class treatment, a relatively more privileged treatment," said Karim Ennarah, of the Egyptian Initiative for Personal Rights.
"But I assume this time it is going to be difficult and more punitive and harsher because the dynamic is different, or because of the perception that they ordered violence against the police or state forces."
(Editing by Ralph Boulton)