A United Nations commission of inquiry on Syria said on Monday Syrian military and security forces had committed crimes against humanity including murder, torture and rape and the government of President Bashar Assad bore responsibility.
Diplomatic sources indicated on Monday that the report would make it harder for China and Russia to further block bids to sanction Syria in the UN Security Council.
The panel, which interviewed 223 victims and witnesses including defectors, called on Syria to halt "gross human rights violations", release prisoners rounded up in mass arrests and allow media, aid workers and rights monitors access to the country.
Syria is "responsible for wrongful acts, including crimes against humanity, committed by members of its military and security forces as documented in the present report," the three-member panel said in a 39-page report to the UN Human Rights Council.
It catalogues executions, torture, rapes including of children, arbitrary detentions and abductions carried out since March by Syrian forces quashing pro-democracy demonstrations while enjoying "systemic impunity" for their crimes, it said.
The commission therefore believes that orders to shoot and otherwise mistreat civilians originated from policies and directives issued at the highest levels of the armed forces and the government," said the team, led by Brazilian expert Paulo Pinheiro.
More than 3,500 people have been killed in the violence, according to the United Nations, while activists say that up to 30,000 have been arrested, many kept in open-air stadiums.
The UN Security Council stopped short of taking action against Syria when China and Russia vetoed a resolution in October. After continuing international criticism of Assad's handling of the crisis, the Arab League approved sanctions against Syria on Sunday.
"The international community must act. More than ever it has a duty to stop the suffering of the civilian population," French Foreign Minister Alain Juppe said in a statement after the publication of the UN report.
In a written response included in the UN report, Syria's mission to the United Nations said Syria was standing against U.S. "policies of occupation" and blamed the violence on "terrorist operations carried out by armed outlaws who are terrorizing our citizens" and trying to "divide the country along sectarian lines and incite civil war."
Syria refused access to the UN investigators, saying it was carrying out its own inquiry. But the UN report pointed the finger squarely at the government of Assad.
"In the Syrian Arab Republic, the high toll of dead and injured is the result of the excessive use of force by state forces in many regions," it said. It called for protecting the Syrian population and for an international embargo on arms sales to Syria.
There had been "isolated instances" of violence by demonstrators, but the "majority of civilians were killed in the context of peaceful demonstrations", it said.
Syrian forces have used snipers and tanks to suppress the uprising and drawn up "black lists" with names of people wanted by the authorities and sought at checkpoints, it said.
"Defectors from the military and security forces told the commission that they had received orders to shoot at unarmed protesters without warning," the report said.
Some soldiers who disobeyed these orders were shot by the security forces or by army snipers, it said. "A number of cases was documented of injured people who were taken to military hospitals, where they were beaten and tortured during interrogation," it said. "Children were also tortured, some to death."
Military and security forces used torture including electric shock and sexual torture, mainly on men and boys in custody, as a "tool to instil fear", the UN panel said.
"Testimonies were received from several men who stated that they had been anally raped with batons and that they had witnessed the rape of boys," it said.
"Detainees were also subjected to psychological torture, including sexual threats against them and their families, and by being forced to worship President Assad instead of their god"," it said.
The inquiry, set up by the UN Human Rights Council last August to probe allegations of crimes against humanity, also called on the 47-member state forum to establish a special rapporteur or investigator on Syria.
The Geneva-based rights forum is expected to hold another special session on Syria, its third, on Friday, at the request of the European Union and other states, according to diplomats and UN sources.
Activist groups, including Amnesty International and Human Rights Watch, said in a letter to United Nations member states last week that if the inquiry found that crimes under international law had been committed, they should urge the Security Council to refer the situation in Syria to the prosecutor of the International Criminal Court.
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