The new report reveals the Syrian government's systematic use of execution and torture.
A team of former international war crimes prosecutors released their findings and ample photo evidence to back their claim that the Assad regime tortured and killed about 11-thousand detainees.
"We came to the conclusion that the killings were of an industrial kind. Such that the evidence we found would certainly underpin any count of a crime at international law."
The photos were taken by a former Syrian military police officer, who has since defected and fled the country.
"And pictures are reminiscent of the worst pictures that came out of Belsen and Auschwitz after the Second World War. And these poor creatures were not only starved but were also tortured while they were starving."
Reacting to the report, the U.S. State Department condemned Syria in the strongest possible terms, saying the photos show apparent actions that would be serious international crimes.
Britain's Foreign Secretary also expressed shock and horror at seeing the report.
"I've seen a lot of this evidence, it is compelling and horrific. And it is important that those who have perpetrated these crimes are one day held to account."
Meanwhile, the world's leading human rights advocacy group has slammed the international community for not doing enough to end the atrocities being committed in Syria.
In its annual report released on Tuesday, Human Rights Watch said world powers have focused too much on bringing President Bashar al-Assad and his government to the negotiating table, and put aside humanitarian matters, such as the protection of civilians.
"What I hope the people gathered in Geneva will do is not simply to try to work out a long-term peace deal. But, in the interim, to put pressure on the Syrian government to stop targeting civilians, to stop deliberately depriving civilians of humanitarian aid."
The group also criticized Syria's close allies, Russia and China, for turning a blind eye to the humanitarian crisis in the country.
Park Ji-won, Arirang News.