South Korea's top nuclear envoy will embark on a five-day visit to China this week, including a rare trip to China's northeastern provinces where thousands of North Korean defectors are believed to be hiding before eventually resettling to the South, Seoul officials said Monday. 

Hwang Joon-kook will leave for a northeastern Chinese city of Shenyang on Tuesday for "meetings with Chinese experts from various sectors, including researchers on Korean Peninsula issues," South Korea's foreign ministry said in a statement. 

Hwang will fly to Beijing on Thursday and hold talks with his Chinese counterpart Wu Dawei on Friday during which they will "extensively discuss the overall situation on the Korean Peninsula, including nuclear and other issues of North Korea," the statement said. 

It is the first time that a South Korean chief nuclear envoy visits Shenyang and other Chinese border towns with North Korea, a senior diplomat at the South Korean Embassy in Beijing said on the condition of anonymity. 

"To my knowledge, it is extremely rare for a South Korean chief nuclear envoy to visit the northeastern provinces in China, which are closely related to the issue of North Korean defectors," the diplomat said, declining to elaborate further. 

China has classified North Korean defectors hiding in border areas as illegal migrants, not asylum-seekers, and routinely returns them to North Korea if they are caught. Back in their home country, they face harsh penalties including even death. Nearly all North Korean defectors walk across the border with China before seeking to resettle in South Korea.

The planned meeting between Hwang and Wu also coincides with a visit by Sydney Seiler, the United States special envoy for the six-party talks on the North Korean nuclear issue, to Beijing on Thursday. 

Seiler was scheduled to arrive in Seoul on Monday as the first leg of his three-nation tour that will also take him to Tokyo. 

The six-party talks, involving South Korea, North Korea, the U.S., China, Russia and Japan, were last held in December 2008.

North Korea has conducted two more nuclear tests since then.

North Korea wants an unconditional resumption of the six-party talks, but South Korea and the U.S. demand that Pyongyang first take concrete steps to show its denuclearization commitment. (Yonhap)