sochi russia leaders iran turkey wednesday support convocation syrian people congress one first step establish inclusive dialogue war-ravaged country russian president vladimir putin say wednesday speak meet iranian counterpart hassan rouhani turkey tayyip erdogan putin say three leaders instruct diplomats security defense body work composition date congress syria leadership commit peace process constitutional reform free elections putin say trilateral meet hold southern russian city sochi three presidents agree step efforts finish terrorist group syria say russia 's putin say iran turkey back propose syrian people congress