Geir Pedersen, The United Nations Special Envoy for Syria, speaks during a Security Council meeting at U.N. headquarters, Thursday, Feb. 28, 2019. (AP Photo/Seth Wenig)
Geir Pedersen, the UN Special Envoy for Syria, speaks during a Security Council meeting on February 28, 2019. AP 

Release of detainees could spearhead new UN push on Syria