Opposition chief Ahmed Moaz al-Khatib took Syria's seat at the Arab League on Tuesday as leaders gathered for the annual summit in Doha gave member states the "right" to arm rebels in the war-torn country.
UN-Arab League peace envoy Lakhdar Brahimi was set to meet top US and Russian officials Friday to discuss the Syrian conflict, a day after Damascus denounced his "bias" against President Bashar al-Assad.
Russian Foreign Minister Sergei Lavrov met in Cairo on Sunday with Arab League chief Nabil al-Arabi for talks about the Syrian conflict, agreeing on the need to move forward but finding little common ground.
UN and Arab League peace envoy Lakhdar Brahimi on Monday begins his Syria mission by meeting League officials and senior Egyptian leaders before heading to Damascus on his first official trip to the region.
UN chief Ban Ki-moon and international envoy Kofi Annan called on the UN Security Council to take strong action on the Syria conflict ahead of a vote Thursday on a western-backed resolution calling for sanctions.