seoul/beijing chinese president xi jinping reply north korean leader kim jong un congratulatory message china communist party congress say hop promote tie two countries north korea state news agency say thursday friendly exchange relatively routine come china come intense pressure unite state rein north missile nuclear test raise tensions globally china increasingly frustrate ally north korea weapons test defiance u.n. resolutions repeatedly call restraint urge side speak act carefully xi message come days u.s. president donald trump make first official visit asia north korea high agenda follow tuesday unexpected agreement seoul beijing move beyond year-long dispute deployment u.s. anti-missile system south korea wish new situation chinese side would make efforts dprk side promote relations two party two countries sustainable soundness stable development thus make positive contribution ... defend regional peace stability common prosperity xi write message date nov. accord north official news agency kcna dprk stand democratic people republic korea north korea official name chinese foreign ministry spokeswoman hua chunying give detail message xi kim confirm send express thank kim congratulatory message many countries send message china congress polite china write back say thank add believe interest side important mean resolve present problem face maintain regional peace stability hua tell daily news brief beijing message yet carry chinese state media thursday afternoon china north korea often exchange diplomatic correspondence ceremonial letter although personal message leaders tend zhao tong north korea expert carnegie-tsinghua center beijing say exchange message appear totally routine note kim congratulatory message short one send previous communist party congress five years ago xi first come power flurry activity include sixth nuclear test sept. pyongyang disrupt last month party congress another test analysts expect test missile since launch one japan sept. 15 long lull year zhao say likely due technical reason rather political reason sign go give additional missile nuclear test say nam seong-wook professor north korea study korea university seoul say xi reply kim could interpret china strategic ambition embrace north korea south korea ahead trump visit south korea china xi previously send message kim recently last year xi express congratulations party congress north korea neither leader visit country since assume power kim send congratulatory message xi last week end china communist party congress wish great success head nation china 's xi say hop promote relations north korea kcna