With North Korea and China set to mark the 70th anniversary of their diplomatic relations... many watchers are speculating North Korean leader Kim Jong-un may travel there this week.<br />Observers say that, if Kim does go,... Pyeongyang may use its close ties with Beijing as leverage ahead of its delayed working-level negotiations with the United States.<br />Lee Seung-jae has the story.<br />North Korean leader Kim Jong-un has visited China four times since assuming power in late 2011.<br />Kim visited China just before his first and second summits with U.S. President Donald Trump,... to show the cooperation between the two communist allies.<br />And with working-level talks between Pyeongyang and Washington tentatively set for some time in the near future,... many speculate Kim may again visit China, and as early as this week.<br />Giving more credence to the speculation, North Korea and China are set to mark the 70th anniversary of the establishment of their diplomatic ties.<br />Observers say it would be the perfect time for the leaders to show their continued cooperation.<br />South Korea's intelligence agency also believes a visit is likely.<br />It could happen before or after October 6th, since the day marks the anniversary of North Korea-China diplomatic relations. Ahead of the first two North Korea-U.S. summits, Kim visited China. Given that precedent, the possibility is there.<br />As a result, many observers say a full resumption of working-level talks between Pyeongyang and Washington will only take place after Kim returns from China.<br />Meanwhile, North Korea's ambassador to the UN has expressed optimism about restarting denuclearization talks with the United States.<br />Speaking in New York on Saturday, local time, Kim Song said he feels "positive" about the resumption of dialogue,... as well as the timing of a possible meeting between the leaders.<br />If Kim heads to China this week,... it's highly likely he will stress the Pyeongyang-Beijing relationship and call for security guarantees from China,... which he may use as a bargaining chip in the regime's negotiations with Washington.<br />Lee Seung-jae, Arirang News.<br />