A report, commissioned by the UN, has found that the Syrian Army is responsible for most of the human rights abuses committed since March.
The report, compiled by a commission appointed by the UN Human Rights Council, looked into human rights violations committed between March and mid-May, and detailed abuses committed by both the government and the rebels.
"Most of the serious human rights violations documented by the Commission in this update were committed by the Syrian army and security services as part of military or search operations conducted in locations known for hosting defectors and/or armed persons, or perceived as supportive of anti-government armed groups," their report said.
"The army employed the wide range of military means, including heavy shelling of civilian areas,
"State security forces continued to use lethal force against anti-government demonstrations in Idlib, Homs, Aleppo, Hama, Damascus and Deraa and in numerous villages throughout the country.
"Whereas government forces had previously been responding primarily to demonstrations, they now face armed and well-organised fighters - bolstered by defectors who joined them,"
The report also accuses opposition forces of committing human rights abuses, including torture and executions of Syrian soldiers.
According to UN estimates, over 10,000 people have died since the start of the uprising in March 2011.