A Human Rights Watch report that identified torture and atrocities in Syria sounded a clear warning that there was "no hiding place" for those responsible for such crimes, William Hague has said.
The rights organisation has carried out more than 200 interviews since the beginning of anti-government demonstrations in the country in March last year.
Accounts from former detainees and defectors have identified the locations, agencies responsible, torture methods used and, in many cases, the commanders in charge of 27 detention facilities run by Syrian intelligence agencies.
The report identified torture by the Syrian intelligence agencies
A 31-year-old detainee who was held in Idlib governorate in June described to Human Rights Watch how the intelligence agencies tortured him in the Idlib Central Prison.
He said: "They forced me to undress. Then they started squeezing my fingers with pliers.
"They put staples in my fingers, chest and ears. I was only allowed to take them out if I spoke. The staples in the ears were the most painful.
"They used two wires hooked up to a car battery to give me electric shocks. They used electric stun-guns on my genitals twice. I thought I would never see my family again. They tortured me like this three times over three days."
Human Rights Watch said the systematic patterns of ill-treatment and torture it had documented clearly pointed to a "state policy of torture and ill-treatment", which constituted "a crime against humanity".
Mr Hague said the UK would work with EU partners to impose sanctions on those responsible to help bring an end to the violence.
The report, Torture Archipelago: Arbitrary Arrests, Torture and Enforced Disappearances in Syria's Underground Prisons since March 2011, includes maps locating detention centres, video accounts from former detainees and sketches of torture techniques described by people who witnessed or experienced torture in the facilities.
Almost all the former detainees interviewed by Human Rights Watch said they had been subjected to torture or witnessed the torture of others during their detention.
Interrogators, guards, and officers used a broad range of torture methods, including prolonged beatings, often with objects such as batons and cables, holding the detainees in painful stress positions for prolonged periods of time, the use of electricity, burning with acid, sexual assault and humiliation, the pulling of fingernails, and mock execution.
Human Rights Watch documented more than 20 distinct torture methods used by the security and intelligence services.
While most of the torture victims interviewed by Human Rights Watch were young men between 18 and 35, the victims interviewed also included children, women, and the elderly.
Ole Solvang, emergencies researcher at Human Rights Watch, said: "The intelligence agencies are running an archipelago of torture centres scattered across the country.
"By publishing their locations, describing the torture methods, and identifying those in charge we are putting those responsible on notice that they will have to answer for these horrific crimes."
Human Rights Watch called on the United Nations Security Council to refer the situation in Syria to the International Criminal Court (ICC) and to adopt targeted sanctions against officials credibly implicated in the abuses.
Commenting on the report, Mr Hague said: "I welcome today's report by Human Rights Watch on the situation in Syria.
"It highlights the horror of what is happening. The scale of the barbaric acts that are being carried out by the regime against the population is appalling.
"This Human Rights Watch report should act as a clear warning. There should be no impunity or hiding place for those committing these crimes.
"Those responsible for systematic and widespread human rights violations should not delude themselves: we and our international partners will do everything we can to ensure that they will face justice.
"Where we have evidence of individuals' responsibility for acts of violence and repression, the UK will work with EU partners to impose sanctions on them.
"We will continue to focus attention on what is happening in Syria and work to bring an end to the violence."
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