Geneva: United Nations High Commissioner for Human Rights Navi Pillay called on Friday for the international community to take action to protect the civilian population in Syria from "ruthless repression" as the country slides into civil war.

More than 4,000 people have been killed, including 307 children, in the military crackdown since March and more than 14,000 people are believed to be held in detention, she told an emergency session of the UN Human Rights Council.

"The Syrian authorities' continual ruthless repression, if not stopped now, can drive the country into a full-fledged civil war. In light of the manifest failure of the Syrian authorities to protect their citizens, the international community needs to take urgent and effective measures to protect the Syrian people," Pillay said.

Pillay, a former UN war crimes judge, said that "the need for international accountability has even greater urgency today".