SEOUL, South Korea -- A delegation dispatched by China's new leader, Xi Jinping, met with the North Korean leader Kim Jong-un on Friday, North Korean state media reported, amid signs that North Korea is stepping up its nuclear and long-range missile programs.
The allies pledged to bolster their ties as Mr. Kim met with Li Jianguo, vice chairman of the Standing Committee of the National People's Congress, and other officials of the Communist Party of China in the North Korean capital, Pyongyang, according to the reports.
Mr. Li delivered a letter from Mr. Xi to Mr. Kim, the North's state-run Korean Central Broadcasting Station reported. South Korean media speculated that Mr. Xi might have invited Mr. Kim to visit China for the first time since assuming power after the death of his father, Kim Jong-il, last December.
North Korea's dependence on China as its main trade partner and source of aid has deepened in recent years as American-led United Nations sanctions have tightened after its recent ballistic missile and nuclear tests.
Washington has urged China to use its influence to persuade North Korea to give up its nuclear weapons program. But while supporting international efforts to end North Korea's nuclear ambitions, Beijing has often been seen by analysts as being more interested in keeping a stable Communist government on its border.
On Thursday, the United Nations' top nuclear official said that North Korea had made additional progress in the construction of a new nuclear reactor, which the country could use to expand its capacity to produce fuel for nuclear weapons.
Yukiya Amano, director general of the International Atomic Energy Agency, told its governing board that North Korea had "largely completed work on the exterior of the main buildings" of a new nuclear reactor under construction in the North's main nuclear complex in Yongbyon, north of Pyongyang, according to Reuters.
Meanwhile, satellite photos indicated that North Korea had moved two sections of a long-range rocket in possible preparation for a launching, the U.S.-Korea Institute at Johns Hopkins School of Advanced International Studies said on its Web site.
The North launched a rocket in April, but it disintegrated shortly after takeoff, failing in its stated goal of putting a satellite into orbit. Washington believes that North Korea's true purpose in conducting the launchings has been to master intercontinental ballistic missile technology.
This article originally appeared in The New York Times.