BEIJING, Sept. 22 (Yonhap) -- A key North Korean party official, who oversees Pyongyang’s foreign policy, returned home from Beijing on Monday, wrapping up his five-nation tour but without meeting with Chinese officials, a a diplomatic source said Monday.

 The absence of a meeting between Kang Sok-ju, the secretary handling international relations at the North’s ruling Workers’ Party, and Chinese officials on the way to or from the trip represented strained political relations between Pyongyang and Beijing, the source said on the condition of anonymity. 

 Kang arrived in Beijing on Sunday from Ulaanbaatar, the final leg of his five-nation tour that had taken him to Belgium, Switzerland, Germany and Italy, and flew to Pyongyang on Monday via an Air Koryo flight, the source said.

 When Kang left for Germany on Sept. 6, he had been anticipated to meet with Wang Jiarui, head of the Chinese Communist Party’s international department, in Beijing because the Chinese capital serves as the only gateway to the isolated North Korea.

 “To my knowledge, Kang didn’t hold a meeting with senior Chinese officials, including Wang, during his trip,” said the South Korean diplomatic source who was briefed by the Chinese side.

 Political ties between North Korea and China became strained over the North’s third nuclear test in February last year and the execution of the North Korean leader’s once-powerful uncle, Jang Song-thaek, who had close ties with Beijing. 

 China, North Korea’s last-remaining patron, supplies nearly all of the North’s energy needs, but Beijing has been unsuccessful in getting Pyongyang to give up its nuclear weapons program.
 The execution of Jang in December last year caused North Korea’s political ties with China to deteriorate further because Jang played the most important role as a conduit between the two nations.

 This month’s rare overseas trip by Kang suggested that North Korea may take a more proactive diplomacy, but South Korean officials described it as an attempt to break its isolation.

 Kang, the key architect of North Korea’s nuclear diplomacy, brokered a nuclear deal in Geneva with the United States in 1994.