U.N. High Commissioner for Human Rights Navi Pillay said Wednesday her office estimates that 59,648 people were killed in Syria from March 15-Nov. 30.
"Given there has been no let-up 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 said in a statement. "The number of casualties is much higher than we expected, and is truly shocking."
Pillay said it was difficult to obtain a comprehensive assessment on what may amount to war crimes in Syria given the severity of the violence. She said the number of deaths in Syria could have been avoid had the Syrian government of President Bashar Assad chose "a different path."
Assad's government is suspected of widespread war crimes during the conflict, though rebel forces are accused of committing atrocities as well.
Bassam al-Dada, a political adviser for the rebel Free Syrian Army, told Turkey's state-run Anatolia news agency that opposition forces could compile materials needed to manufacture chemical weapons.
"If we ever use them, we will only hit the regime's bases and centers," he was quoted as saying.
Civil war in Syria is descending on the capital Damascus as support for a political opposition council grows.