sochi russia three-way summit wednesday leaders russia iran turkey could produce decisive step toward end bloodshed syria turkish president tayyip erdogan say start talk summit host russian president vladimir putin rare occasion bring together leaders russia iran back syria president bashar al-assad around table erdogan support assad opponents open remark summit southern russian resort sochi putin erdogan iran president hassan rouhani speak open peace syria islamic state push last major stronghold point reach important enough erdogan tell gather also attend military commanders foreign minister three countries critical party contribute permanent acceptable political solution people syria say summit aim result believe critical decisions take prelude summit putin early week host assad residence sochi time syrian leader know leave syria since last visit russia two years ago putin also make telephone call past 24 hours leaders influence syria include u.s. president donald trump saudi arabia king salman part moscow drive build international consensus peace deal end six-year conflict say certainty reach new stage open possibility launch real political process towards peace deal putin tell gather compromise concessions need side ... include syrian government putin say say focus peace efforts convocation congress bring together syria ethnic group russia offer host congress sochi attempt agree date far founder part turkey raise objections presence kurdish group iran rouhani use remark summit rail presence foreign force syria apparent reference unite state tehran arch regional rival saudi arabia alongside turkey back assad foes excuse presence foreign troop syria without approval legitimate government rouhani say syrian nation allow interference foreigners state affairs confront move harm syria integrity independence unity say iran military also present syria alongside russian troop hezbollah pro-iran lebanese militia say amount foreign interference syria assad invitation russia-hosted summit could decisive syria peace erdogan