As many as 13,000 people were hanged in five years at a notorious Syrian government prison near Damascus, Amnesty International said Tuesday, accusing the regime of a "policy of extermination."

Titled "Human Slaughterhouse: Mass hanging and extermination at Saydnaya prison," Amnesty's damning report is based on interviews with 84 witnesses, including guards, detainees, and judges.

It found that at least once a week between 2011 and 2015, groups of up to 50 people were taken out of their prison cells for arbitrary trials, beaten, then hanged "in the middle of the night and in total secrecy."

"Throughout this process, they remain blindfolded. They do not know when or how they will die until the noose was placed around their necks," the rights group wrote.

The group has previously said that more than 17,700 people were estimated to have died in government custody across Syria since the country's conflict erupted in March 2011.


The figure of 13,000 deaths in a single prison, therefore, is a marked increase.
"The horrors depicted in this report reveal a hidden, monstrous campaign, authorised 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's Beirut office.

"The cold-blooded killing of thousands of defenceless prisoners, along with the carefully crafted and systematic programmes of psychological and physical torture that are in place inside Saydnaya Prison cannot be allowed to continue," she said.


A probe by the United Nations last year accused Assad's government of a policy of "extermination" in its jails.


More than 310,000 people have been killed and millions have fled their homes since the conflict began with anti-Assad protests.