The face of the Arab spring in Syria: Torture victim, aged 13

Hamza al-Khatib was only 13 when, claim activists, he was tortured and killed by the Syrian security forces.

A snapshot of the teenager now emblazons posters of protest across the Middle East country after a YouTube video of his bloodied corpse sparked outrage. Syrian authorities deny he was tortured, saying he was killed at a demonstration in which armed gangs fired upon state guards.

Hamza, like the market-seller Mohamed Bouazizi who set himself alight in Tunisia and Neda Agha Soltan, whose dying moments were filmed and distributed in Iran, has become a potent symbol to protesters demanding more freedom.

The video shows his bloated body, with bullet wounds to his arms, stomach and chest as well as bruising to his face and legs. Two men, who seem to be medical examiners, then say his genitals were mutilated, though the image is pixilated.

"Look at these reforms that the treacherous Bashar has called for," one of the examiners is heard saying in the video, apparently taken on 25 May. Hamza disappeared at a protest on 29 April and his body was returned to his family only in the past week.

"Uprisings need symbols… These individual cases are symptomatic and represent hundreds of other cases that may go unreported that are just as horrendous," said Human Rights Watch's senior Syria and Lebanon researcher, Nadim Houry.

He said: "What's more important is that this is part of a broader pattern which shows how systematic torture has been for people detained in (the city of] Deraa, including children.

"It raises alarm bells that there are still hundreds of people, if not more, whose fate is still unknown."

Rights groups say more than 10,000 people have been arrested in ten weeks of protests raging in many parts of Syria and estimate some 1,000 civilians have been killed - an 11-year-old girl, Malak Munir al-Qaddah, was reportedly killed in the southern town of Hirak yesterday.

Radwan Ziadeh, head of the Syrian Centre for Political and Strategic Studies, said: "The regime commits two types of torture, the systematic, which we see accompanying mass arrests, and the particularly gruesome to spread fear on an even larger scale. The Hamza case belongs to the latter."

Hamza was from Deraa, an agricultural city in the south near the border with Jordan, where the freedom protests first erupted on 18 March.Human Rights Watch yesterday published a report based on more than 50 interviews with victims and witnesses to abuse that show "systematic killings and torture by Syrian security forces in the city of Deraa", which it said strongly suggested they qualified as crimes against humanity.

"They need to stop - and if they don't, it is the (United Nations] Security Council's responsibility to make sure that the people responsible face justice," said Sarah Leah Whitson, the group's Middle East director.

Syrian authorities say armed groups backed by Islamists and foreign powers are responsible for the violence and have killed civilians and security personnel.

Clearly rattled by the claims, Syrian state television aired on Tuesday night a programme about Hamza in which a judge, Samer Abbas, said the boy's death was due to "a number of bullet wounds without any indication of torture or beating on the body".

He said the body was handed to the family on 21 May.

Coroner Akram al-Shaar backed this up, according to a transcript on the state news agency. Mr Shaar said: "There are no marks on the surface of the body that show violence, resistance or torture using the nails or scratching or bruises, or fractures, or joint dislocation."

A man who identified himself as Hamza's father on Syrian television said he had met president Bashar al-Assad who "engulfed us with his kindness, graciousness and promised to fulfil the demands which we've called for with the people".

"The president considered Hamza his own son and was deeply affected," the man said, adding he had promised reforms would start the very next day.

Wissam Tarif of the Insan human rights group said Hamza's killing would spur more protests. He said: "Hamza is a symbol now, definitely. There are no red lines, the regime can be as brutal as it wants, it will kill and torture children. People are aware of that, but what can they do, go back home? The wall of fear cannot be built again. The protests are not reversible."