Omar Alshogre is shown in the left image in July 2015 and in the right image in January 2017, one month after he got out of Syria’s Saydnaya prison. (Omar Alshogre /via Associated Press)

AMNESTY INTERNATIONAL calls it the “human slaughterhouse”: a Syrian military prison where thousands of civilians have been killed “after being repeatedly tortured and systematically deprived of food, water, medicine and medical care.” Allegations of atrocities against civilians are nothing new for the regime of Bashar al-Assad, which has subjected entire towns to starvation sieges, dropped barrel bombs full of nails or chlorine on hospitals, supermarkets and schools and pulverized a U.N. aid convoy during the recent siege of Aleppo. But the story of the Saydnaya military prison deserves attention, if only because it shows the regime’s calculated sadism and cold determination to exterminate all who oppose it.

Amnesty’s report, based on a year of research and 84 interviews with former Saydnaya prisoners, guards, judges, doctors and others, estimates that between 5,000 and 13,000 civilians were extrajudicially executed at the facility outside of Damascus between September 2011 and December 2015 — and there is no reason to believe the killings have stopped since then. These were not rebel fighters, but civilians perceived to oppose the government in some way: participants in demonstrations, dissidents, human rights advocates, journalists.

The victims were mostly abducted by security forces, tortured into confessions and rushed through “trials” that often lasted only two or three minutes, according to Amnesty. They were secretly executed in groups of 20 to 50: First blindfolded and then badly beaten, they were told only at the last moment that they were to be hanged, when a noose was slipped around their necks. Many died before execution from the horrific conditions in the prison, including starvation and rape. Amnesty said it had concluded that the detainees had been subjected to a policy of “extermination,” defined in international law as measures “calculated to bring about the destruction of part of a population.” Their bodies were dumped in mass graves.

Amnesty said it collected information on officials who sat on the execution panels and others involved in the executions, which it described as crimes against humanity. That gives reason for hope that some will eventually be brought to justice; in other parts of the world such atrocities have been successfully prosecuted decades after they occurred. In the meantime, the Saydnaya report should be considered by all those who believe that the Syrian civil war — with its endless carnage, breeding of terrorism and waves of refugees — can be brought to an end while the Assad regime remains in power.

The horrific abuses inflicted by the regime on tens of thousands of Syrians ensure that it will never be tolerated by the vast majority of the population. Its barbaric practices render it unable to compromise with people it has attempted to murder en masse. A decision by the Trump administration to tolerate or even support the butchers of Damascus will only result in more warfare, more recruits for the Islamic State and al-Qaeda, and more unconscionable murders at Saydnaya prison.