beijing unite state must respect china concern taiwan avoid cause disturbances sino-u.s. tie chinese foreign minister wang yi tell visit u.s. secretary state rex tillerson saturday china consider democratic taiwan wayward province never renounce use force bring island control unite state formal tie taiwan bind law help defend island main source arm china regularly call taiwan sensitive important issue unite state upset u.s. move expand military exchange taiwan continue u.s. arm sales island wang explain china position taiwan issue demand u.s. side earnestly respect china concern appropriately handle relevant issue avoid bring disturbances china-u.s. relations china foreign ministry say elaborate beijing relationship taiwan frosty since president tsai ing-wen election island landslide last year china suspect tsai lead pro-independence democratic progressive party want declare island formal independence red line beijing tsai say want maintain peace china recent months chinese air force conduct series drill around taiwan include bombers advance fighter jet alarm taipei china call exercise routine pledge continue china say u.s. respect concern taiwan