The North Korean ambassador to Britain, Hyon Hak-bong, arrived in Beijing on Saturday after a trip to Pyongyang, a diplomatic source said, adding that his trip was unrelated to the recent execution of leader Kim Jong-un's uncle in a dramatic political purge.

Hyon, who took up the post in December 2011, was seen arriving at the Beijing airport earlier in the day on an Air Koryo flight from Pyongyang. He didn't respond to questions by a group of journalists.

"To my knowledge, a number of ambassadors, including Ambassador Hyon, returned to North Korea in the wake of the New Year season to study the New Year's Day message by Kim Jong-un," the source said on condition of anonymity.

Kim's once-powerful uncle, Jang Song-thaek, was purged and executed last month on charges of attempting to overthrow the regime, raising concerns over the North's internal stability.

North Korea had recalled some ambassadors who were close to Jang, including Jang Yong-chol, the North Korean ambassador to Malaysia who is a nephew of the purged uncle. (Yonhap News)