North Korea publicly executed six officials in charge of supervision of its workers overseas in May following the defection of 13 workers at a North Korean-run restaurant in China a month earlier, a local Pyongyang watcher said Friday.

"North Korean leader Kim Jong-un ordered six officials, including intelligence officials, to be executed publicly on May 5 due to their lack of control over overseas (North Korean) workers," Choi Seong-yong, chairman of the Abductees' Family Union, claimed, citing people familiar with the matter.

Eighty public officials and 100 people who have their family members working overseas were forced to watch the execution, he said.

In early April, a group of 12 women and one man fled from a North Korea-run restaurant in China's eastern port city of Ningbo and defected to South Korea. In the following month, three female workers at a North Korean restaurant in the midwest city of Shanxi reportedly defected to the South.

"North Korea locked the families of the defectors up and forced them to take ideological education at a training facility in Myohyang Mountain, in the northern part of the communist country," Choi said.

The North Korean authorities have argued the workers didn't defect to the South but were kidnapped by the South Korean government. (Yonhap)