The delegation arrived in Pyongyang via the Sinuiju border crossing on Thursday, KCNA reported, without specifying any details.
The current visit might be in return to North Korean Vice Foreign Minister Pak Myong Ho's trip to China in December 2023, South Korean news agency Yonhap reported.
While in Pyongyang, Sun is expected to meet with high-ranking North Korean officials and pay a visit of honor to the country's leader, Kim Jong Un, Yonhap reported.