The U.N. human rights chief pressed Syrian officials again on Friday to let observers enter the country and reiterated her concerns the conflict could erupt in civil war.
In a briefing with reporters, U.N. High Commissioner for Human Rights Navi Pillay also confirmed the government's estimate that nearly 1,000 security forces had been killed in the clashes inside the country.
Pillay estimates that more than 4,000 people on all sides have died in the nine-month conflict.
"Almost 1,000 of President (Bashar) Assad's security forces have also been killed in this conflict," Pillay said. "This is why I am alerting the world that as you have more and more defectors from the security forces, this may well develop into a fully fledged civil war."
Activists say Syrian security forces fired on anti-government demonstrations across the country on Friday, killing at least 24 people, including several children.