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.
The Syrian war is now twice as bloody as that which put an end to the regime of Col Muammar Gaddafi in Libya last year, despite the involvement of concentrated NATO air power.
The rate of killing has gathered pace as the uprising has turned into a civil war involving fighter jets, helicopter gunships and car bombs. In the summer of 2011, there were about 1,000 deaths per month, but since July 2012 this had risen to an average of more than 5,000.
Navi Pillay who is the U.N. High Commissioner for Human Rights said “The number of casualties is much higher than we expected, and is truly shocking.”
“The failure of the international community, in particular the [UN] Security Council, to take concrete actions to stop the blood-letting, shames us all,’ Ms Pillay added. ‘Collectively, we have fiddled at the edges while Syria burns.’
Navi Pillay warned thousands more would die unless immediate action was taken to protect Syrian citizens.