"This report is extremely alarming, and the alleged scale of the deaths in detention, if verified, is truly horrifying," Rupert Colville, spokesman for UN rights chief Navi Pillay, told AFP in an email.
"Allegations this serious cannot be ignored and further investigation is clearly necessary," he added.
The report by three international prosecutors -- commissioned by opposition-backer Qatar and based on some 55,000 digital images from a defector -- charges that President Bashar al-Assad's regime is guilty of the "industrial scale" torture and killing of 11,000 detainees.
It was released a day before a long-awaited international peace conference aimed at negotiating an end to Syria's bloody civil war was due to begin in the Swiss town of Montreux.
Syria has previously denied torturing detainees but the government had no immediate reaction to the report.
Both Pillay's office and an independent commission of inquiry on Syria, appointed by the UN Human Rights Council in Geneva in 2011, have already documented a number of cases of torture similar to those described in the report, but not on such a large scale.
It has never gained access to Syria, but through more than 2,000 interviews in the surrounding region or by phone or Skype it concluded that regime forces have applied torture, including electric shocks, cigarette burns, sleep deprivation and mock executions, Colville pointed out.
The UN investigators, who found that reported deaths in Syrian custody rose markedly in 2013, have also accused the opposition of war crimes, and Pillay expressed deep concern last week that some anti-government armed groups were increasingly torturing and murdering people in their custody.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
