GENEVA — More than 60,000 people have died in Syria’s 22-month-old civil war, the United Nations’ human rights chief, Navi Pillay, said on Wednesday, expressing dismay at the findings of an analysis that far exceeds previous estimates of casualties.

“The number of casualties is much higher than we expected, and is truly shocking,” Ms. Pillay, the United Nations high commissioner for human rights, said in a statement that condemned the government of President Bashar al-Assad for the scale of the carnage and sharply admonished the United Nations Security Council for failing to act.

"The failure of the international community, in particular the Security Council, to take concrete actions to stop the bloodletting, shames us all,” she said.

An “exhaustive analysis” of casualties in Syria documented 59,648 killings between mid-March 2011 and the end of November, Ms. Pillay reported. “Given there has been no letup in the conflict since the end of November, we can assume that more than 60,000 people have been killed by the beginning of 2013,” she added.