The North Korean ambassador to China, Ji Jae-ryong, was tightlipped when asked about the state visit to South Korea by Chinese President Xi Jinping this week.

Ji, who showed up at a ceremony hosted by Xi at the Great Hall of People on Saturday evening, was repeatedly asked by some South Korean correspondents about the upcoming summit talks between South Korean President Park Geun-hye and Xi, but he didn't respond to any of the questions.

Xi is scheduled to make a two-day visit to South Korea from Thursday for the summit talks that are expected to focus on how to further boost their relations and how to deal with North Korea's nuclear weapons program.

It would be the first time in more than two decades for a sitting Chinese president to visit South Korea before traveling to North Korea, a last-remaining ally of China.

Some analysts say Xi's visit to South Korea and his no visit to North Korea as Chinese president appear to represent a change in China's political power balance on the Korean Peninsula.

Asked about Xi's visit to Seoul before making a trip to Pyongyang as Chinese president, China's foreign ministry spokesman Qin Gang replied on Friday, "As a close neighbor to both South Korea and North Korea, our position on the Korean Peninsula issue is consistent, clear and objective."

"We are committed to peace and stability on the Korean Peninsula," Qin said. "China will continue our friendly and cooperative relations with both sides, and stands ready to work with them to push forward China-South Korea and China-North Korea relations."

Xi first visited Pyongyang in 2008 when he was vice president.

Kim Jong-un, who took over North Korea in 2011 after the sudden death of his father and long-time leader Kim Jong-il, has yet to be invited to Beijing.

Park has met with Xi four times since they took office in 2013. (Yonhap)