A top North Korean official was believed to have fled the country, now likely in China, RFA reported Friday.

Suh Kyung-suk, first secretary of Ryanggang-do region of the Kim Il-sung Socialist Youth League, the youth wing of the Workers Party, has disappeared since May 19, it said.

His disappearance sparked "emergency search" by the North's security apparatus, according to a North Korean who lives in South Korea and has been maintaining contact with him.

Given the serious nature of the incident, he said, North Korean agents have even went into China, looking for him.

Since Suh's disappearance, North Korea has also enhanced mobile phone surveillance, it said. North Korean defection is normally coordinated by groups in China that use Chinese mobile phone signals that reach the North's cities along the Chinese borders.

Suh's defection is motivated by his corruption, which was reported to the higher authorities, prompting him to escape before they could come to arrest him, according to Daily NK, an Internet Web site run by North Korean defectors in South Korea.