"Where previously victims were targeted on the basis of their being pro- or anti-government, the (Commission of Inquiry) has recorded a growing number of incidents where victims appear to have been targeted because of their religious affiliation," the report said, describing conditions across Syria.
The commission said special envoy Annan's peace initiative "offers the best framework for a resolution of the conflict," and Annan's planned Saturday meeting of the Action Group for Syria will work on steps to implement his six-point peace initiative.
Annan said Wednesday he invited the top diplomats of the five permanent members of the Security Council -- China, France, Russia, the United Kingdom and the United States -- and Turkey. Envoys from the United Nations, European Union, and Arab League also were invited.
The Action Group for Syria should "agree on guidelines and principles for a Syrian-led political transition that meets the legitimate aspirations of the Syrian people; and agree on actions that will make these objectives a reality on the ground," Annan said. "I look forward to a productive meeting this weekend, where we can all agree on concrete actions to end the cycle of violence and bring peace and stability to the Syrian people."
U.S. Secretary of State Hillary Clinton plans to attend the meeting.
Speaking in Helsinki, Finland, she said that, if participants can meet on the basis of laying out a road map to a political transition in Syria, "then a meeting makes a lot of sense" and "could be a turning point." A transition road map backed by Russia and China, which have blocked tough previous attempts by the Security Council to act against Syria, would send a strong message to the al-Assad regime, she said.
Annan had wanted to invite Iran to the meeting, but the United States opposed that, noting Tehran's support for al-Assad's forces.
Asked about U.S. opposition, Iranian U.N. Ambassador Mohammad Khazaee told reporters, "A very important fact that cannot be ignored by anybody is the influence and constructive law that the Islamic Republic of Iran has on the region. So, if some powers do not want to benefit from this influence and constructive law, that is their problem."
He cited "foreign interventions, supporting financially and militarily the opposition groups and terrorist groups in Syria" as the major cause of Syria's problem.
The United Nations estimates more than 10,000 people have been killed since the Syrian crisis began in March 2011. Opposition activists say the death toll has exceeded 15,000, most of them civilians. About 1.5 million Syrians "are in need of urgent humanitarian assistance," said Jean-Marie Guehenno, U.N.-Arab League deputy envoy to Syria.