The number of Syrians tortured to death since the outbreak of the March 2011 uprising has reached 11,429, said a report by UK-based Syrian Network for Human Rights (SNHR).

The overwhelming majority of the victims had suffered at the hands of forces loyal to President Bashar al-Assad, SNHR noted.

The report, released on 26 June and titled "The United Nations International Day in Support of Victims of Torture", said the victims included 157 children and 62 women.

Islamic State militants and various rebel groups also tortured tens of people, regardless of their age and sex, the report said.

Three or four Syrians on average die because of torture every day, according to the report, which stressed that the worst types of tortures worldwide have been observed in Syria.

Torture is one method of killing by pro-government forces, SNHR Head Fadhil Abdulghani said in the report.

According to UN, torture is a crime under international law; it is absolutely prohibited and cannot be justified under any circumstances.

Meanwhile, the European parliament reportedly rejected holding in its public exhibition areas a major public show of photographs that document torture in Assad's government institutions, deeming then too "disturbing".

A similar exhibition, however, was allowed to take place at the UN headquarters in New York in March.

Separately, a number of Syrian witnesses told Vanity Fair magazine of the horrors that were taking place in some of Syria's military hospitals, where they had worked before fleeing the country.

Some of the tortured victims "had acid on their hips. I could see straight through to the bone," one witness recalled, while another witnessed "wrapping men’s genitals so tightly with a rubber glove that the pressure would cut off circulation".

"Sometimes the Mukhabarat [Syrian intelligence] guys would pee on the wounds. Other times they would dip a prisoner’s bandages in toilet water and put them back on," one witness told the magazine.

Sometimes even the torturers were subjected to suffering. On one occasion, a lieutenant in the Syrian intelligence was ordered to torture his own cousin, who was suspected of belonging to the opposition.