Saydnaya Military Prison — nicknamed “the slaughterhouse” — is where the Syrian government has carried out the mass extermination of ordinary civilians from 2011 to 2015. According to a new report released on Tuesday by Amnesty International, an estimated 13,000 people alone have died at this military prison north of Damascus. That means 20-50 detainees were hanged each week on orders from senior Syrian officials.

Those figures alone surpass the death toll recorded at Plaszow Labor Camp in Poland during the Holocaust.

The victims — doctors, journalists, political dissidents, aid workers, and more — were all believed to oppose the government of President Bashar Assad in some way, even if that meant simply opposing the carnage.

Every week in Syria’s #Saydnaya prison, 20-50 people are hanged. Don’t let the authorities get away with murder: https://t.co/GoW4XkcNK6pic.twitter.com/nbVokJkqRZ

— AmnestyInternational (@amnesty) February 7, 2017

“The horrors depicted in this report reveal a hidden, monstrous campaign, authorized at the highest levels of the Syrian government, aimed at crushing any form of dissent within the Syrian population,” said Lynn Maalouf, Deputy Director for Research at Amnesty International’s regional office in Beirut, in the report.

Hangings at Saydnaya are carried out once or twice a week, in total secrecy under the cover of night. Those whose names were called out by military police were told they would be transferred to civilian prisons in Syria. Blindfolded, they were savagely beaten and transported to another prison building on the grounds where they were then hanged.

"These executions take place after a sham trial that lasts over a minute or two minutes, but they are authorized by the highest levels of authority," including the Grand Mufti, a top religious authority in Syria, and the defense minister, Maalouf said.

The report includes graphic details of torture. Food and water were regularly cut off. The food that was delivered was left scattered on the floor among dirt and blood. Rape and psychological degradation were an atrociously common practice. Prisoners were not allowed to make any sounds and even a slight glance at a guard was punishable by death. Those who survived came back half of their weight.

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The horrifying accounts were gathered by Amnesty after a yearlong investigation. The organization interviewed 84 people — 31 of them former detainees, four of them prison officials or guards and 22 of them family members of current detainees. These families are never given any information about the fate of their imprisoned loved ones.

Former military officer, Hamid*, recounted: “If you put your ears on the floor, you could hear the sound of a kind of gurgling. This would last around 10 minutes… We were sleeping on top of the sound of people choking to death. This was normal for me then.” Hamid* was arrested in 2011.

Although the most recent data is from 2015, Maalouf said there is no reason to believe the practice has stopped since then. The scale of the horror could be much larger, as well.

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Torture, disappearance, and death are not new for Syria. In a report last year, Amnesty found that more than 17,000 people across Syria have died of ill-treatment since 2011. That’s a staggering 300 deaths a month.

Since the civil war began in 2011, the Syrian UN Envoy claims that an estimated 400,000 people have died. As of Dec. 2016, 4.81 million Syrians have fled the country and 6.3 million are displaced internally.

In the past, the Syrian government has denied the reports documented by multiple international human rights groups, writing them off as propaganda. The report says that upon trying to make contact with the government about the allegations in Jan. 2017, they received no response.

Amnesty pleads with the international community, notably the UN Security Council, that they “must take immediate and urgent action, to put an end to this suffering.”

* indicates name has been changed to protect identities.