Families of some protesters detained during the November unrest in Iran have been denied any information about them and fear they are dead, others who have been released say they were tortured to make self-incriminating confessions.

Thousands of protesters were arrested across Iran during anti-government demonstrations in mid-November and hundreds were killed. Iranian authorities have still not announced the number of detained protesters or the death toll.

According to Radio Farda's estimates, at least 8,600 protesters were detained in 22 Iranian provinces. Human rights activists have so far compiled a list with of more than 500 protesters whose deaths have been confirmed. The list is available on Farsi Wikipedia and is regularly updated.

"We and families do not have any information on the situation of some of the people who spread the news, videos and photos of the protests. We don't know where they are held. We only know they are held by the Revolutionary Guard Intelligence Organization," the report quoted Karim Deihimi, a human rights activist in Khuzestan, as saying.

The regime crackdown was very intense in the oil-rich Khuzestan Province and the number of arrests and death toll were particularly high.

Deihimi also said some of the missing individuals were taken from Moarefizadeh Hospital in Shadegan. "Families are in total darkness and seriously concerned that they might be among the dead," he said and added that the authorities refuse to provide any information to these families.

In its latest report the U.S.-based Center for Human Rights in Iran, formerly known as International Campaign for Human Rights in Iran (ICHRI), stated that according to its sources in the country, detainees in Tehran Province are held at two notoriously overcrowded prisons, Qarchak and Fashafuyeh, a former camp for drug inmates, in the south of the capital.

Mohammad-Hossein Aghasi, a lawyer in Tehran, has told the rights group that bails set for many of the protesters are too high for them or their families to afford.

The report quotes an unnamed lawyer in Tehran as saying that although some of the detainees with lesser charges have been freed on bail, the number of those in detention is still very high.

Three branches of the Revolutionary Court which formerly dealt with drug-related crimes have been tasked with investigating those arrested in November protests due to the huge number of detainees still in custody, the unnamed lawyer is quoted by the report as saying.

The unnamed lawyer said a number of his clients had been identified from videos and CCTV footage during or after the protests and added that there is another group which security and judicial officials call "leaders of riots". The cases of these individuals have not been referred to any court with due process and legal counsel denied to them, he said.

Another lawyer who also represents some of the detainees in Tehran told the rights group that in some cases detainees have been charged with "insulting the Supreme Leader", "propaganda against the system", and "insulting sanctitities".

Some protesters who were freed on bail say they were subjected to physical and psychological torture to "confess" to having connections with "hostile networks abroad", the report says and quotes a lawyer as saying that some of the detainees have been charged without any evidence other than their own "confessions" or mere presence in the protests.

Some of the protesters who have been freed on bail have told the rights group that the Revolutionary Court has charged them with "disturbing public order", "destruction of public property", and "conspiracy to commit crimes against national security".