More than 60,000 people have been killed in Syria since the uprising against President Bashar al-Assad's regime erupted in March 2011, the UN High Commissioner for Human Rights has said.
She added that "once there is peace in Syria, further investigations will be necessary to discover precisely how many people have died, and in what circumstances, and who was responsible for all the crimes that have been committed".
The analysis - which Pillay stressed is "a work in progress, not a final product" - shows a steady increase in the average number of documented deaths per month since the beginning of the conflict, from around 1,000 per month in the summer of 2011 to an average of more than 5,000 per month since July 2012.
Syria burns
The greatest number of reported killings have occurred in Homs (12,560), rural Damascus (10,862) and Idlib (7,686), followed by Aleppo (6,188), Daraa (6,034) and Hama (5,080), the analysis found.
"This massive loss of life could have been avoided if the Syrian government had chosen to take a different path than one of ruthless suppression of what were initially peaceful and legitimate protests by unarmed civilians," Pillay said.
"As the situation has continued to degenerate, increasing numbers have also been killed by anti-government armed groups, and there has been a proliferation of serious crimes including war crimes, and - most probably - crimes against humanity, by both sides."
Pillay also criticized the international community for failing to do more to stop the crisis, saying: "Collectively, we have fiddled at the edges while Syria burns."
Her comments came as activists reported on Wednesday the deaths and injury of dozens of people in an airstrike on a petrol station in the suburbs of Damascus.
PHOTO CAPTION
Rupert Colville, the UN human rights spokesman
Aljazeera