washington unite state tuesday seek downplay absence talk syrian conflict among russia iran turkey moscow say snub reflect decline u.s. influence middle east however president barack obama decision offer limit support moderate rebel leave washington little leverage influence situation syria especially moscow begin launch air strike rebel fight president bashar al-assad although washington long player efforts end syria civil war mideast conflict unite state force watch sideline syrian government ally include russia mount assault pin rebel east aleppo culminate ceasefire deal dennis ross fellow washington institute near east policy adviser iran middle east democratic republican administrations say unite state make irrelevant syria opposition find little reason responsive us assad russians iran know nothing raise cost onslaught aleppo syrian cities ross say russia change balance power grind without regard civilian consequences move make arbiter spokesman u.s. secretary state john kerry dismiss suggestions america absence meet indicate change influence secretary see snub see another multilateral effort try get last peace syria welcome progress towards state department spokesman john kirby say tuesday would obviously refute notion ... fact one meet somehow harbinger litmus test u.s. influence leadership anywhere else around world kirby say add washington still engage region many issue exclude sideline add meet tuesday russia iran turkey say ready help broke syrian peace deal adopt declaration lay principles agreement follow still meet tuesday result moscow declaration reflect russia grow link iran turkey despite murder monday russia ambassador ankara turkey capital reflect putin desire increase country influence middle east widely also show russia feed consider long pointless talk obama administration syria u.s. official acknowledge u.s. absence evacuation talk eastern aleppo russia way show moscow washington run show fact put position russia make efforts try work anybody else isolate us official speak condition anonymity tell reuters let differences turkey kurds view northern part syria create gap russians exploit kirby say end unite state russia iran turkey would like see immediate ceasefire urgent delivery humanitarian aid ultimately say soon judge whether talk success russian president vladimir putin say last week turkish counterpart tayyip erdogan work organize new syrian peace negotiations without unite state unite nations russia say happen talk would addition intermittent u.n.-brokered negotiations geneva russian foreign minister sergei lavrov say tuesday think call russia-iran-turkey troika effective forum try solve syria crisis u.s. play absence moscow talk syria say 'sidelined