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."

In a report on Saydnaya prison based on interviews with 84 witnesses, the rights group 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".