A protest movement that grew out of the Arab Spring has pushed Syria into civil war. The United Nations estimates that at least 70,000 people have died and another 1 million have been displaced by war.
The International Federation for Human Rights, known by its French initials FIDH, said it was calling for a global "stop to the massacres" campaign to mark the second anniversary of the war Friday.
"Tens of thousands of others have been detained or disappeared, thousands of Syrians have been submitted to torture and ill-treatments, sexual violence and looting," FIDH said.
U.N. High Commissioner for Refugees Antonio Guterres said the refugee crisis could rise exponentially if the conflict continues unabated.
"If this escalation goes on and nothing happens to solve the problem we might have in the end of the year a much larger number of refugees -- twice or three times the present level," he was quoted by the BBC as saying from Turkey.