By Stephanie Nebehay
GENEVA (Reuters) - Syrian security forces have used executions, mass arrests and torture to repress pro-democracy protests, the U.N. human rights office said on Wednesday, in a report that could add to calls for a stronger global response.
Entire towns have been besieged, including Deraa, preventing civilians from fleeing and depriving many of food supplies and access to medical care, especially the wounded, it said.
More than 1,100 people are believed to have been killed, many of them unarmed civilians, and up to 10,000 detained since the crackdown by President Bashar al-Assad began in mid-March, United Nations High Commissioner for Human Rights Navi Pillay said, reiterating figures she issued last week.
The main Syrian activist group organizing protests said on Sunday the crackdown has killed 1,300 civilians.
"The mounting casualty rate among civilians is alarming," Pillay said in a speech to the U.N. Human Rights Council.
"I am gravely concerned about the human rights and humanitarian crises that the country is facing."
In a report to the 47-member forum, her office said it had received numerous allegations of violations by Syrian forces, including "the excessive use of force in quelling demonstrators, arbitrary detentions, summary executions, torture" and a clampdown on freedoms of assembly and expression.
"The most egregious reports concern the use of live ammunition against unarmed civilians, including from snipers positioned on rooftops of public buildings and the deployment of tanks in areas densely populated by civilians," the report said.
Helicopter gunships were reported to have been used during a military assault on the northwestern town of Jisr Al-Shughour, driving more than 7,000 Syrians into Turkey, it said.
Syria's government has said that some 120 security personnel were killed by "armed gangs" in the town on June 6 and claimed to have found a mass grave with the remains of about 10, Pillay said. "There are concerns, however, that these might be the bodies of military deserters or officers who disobeyed orders."
Thousands of Syrians fled the historic town of Maarat al-Numaan on Wednesday to escape troops and tanks pushing into the north in a widening military campaign to crush protests.
Syria's delegation to the Human Rights Council did not take the floor on Wednesday.
Pressure is building in the West for a more forceful international response to violence in Syria. Western countries have so far imposed only targeted sanctions against Syrian officials, in contrast to Libya where they launched a military campaign to prevent a crackdown by Muammar Gaddafi's forces.
Canada, speaking on behalf of 45 countries from all regions, called for a credible and impartial investigation into "daily reports of killings, arbitrary detention and torture" in Syria.
"We call upon the Syrian government to respect the will of its people and to implement reforms, taking meaningful steps to end censorship, restrictions on journalists and independent observers and state control of the media," the statement said.
U.S. ambassador Eileen Chamberlain Donahoe backed Canada's text, adding: "The Syrian government continues to repress the legitimate demands of their people through killings, torture, and arbitrary arrests. We strongly condemn its use of force."
Activists and journalists, and some of their relatives, were among an estimated 10,000 arrested so as to silence critics, although some have been released, according to the U.N. report.
It cited "information indicating that Syrian security forces have perpetrated acts of torture and other cruel and inhuman treatment against persons detained in connection with the demonstrations, resulting in deaths in custody in some cases."
(Editing by Fredrik Dahl and Peter Graff)