BEIRUT (AP) — The United Nations estimated Wednesday that more than 60,000 people have been killed in Syria’s 21-month-old uprising against authoritarian rule, a toll one-third higher than what anti-regime activists had counted. The UN human rights chief called the toll ‘‘truly shocking.’’

Opposition activist groups had been estimating the death toll at more than 45,000 and this was the first time that the UN estimate was higher.