SHANGHAI  A North Korean plane crashed in northern China on Tuesday, killing the pilot, the only person on board, according to China’s state-run Xinhua News Agency.

Yonhap, the South Korean news agency, citing unnamed intelligence sources, said that the plane appeared to be a Soviet-era MiG-21 jet, a craft used by the North’s air force, and that the pilot might have been trying to defect to Russia but lost course.

Although thousands of North Koreans have fled their repressive home country in the past decade and a half, it is highly unusual for an elite pilot to defect. A North Korean pilot flew his MiG-19 to defect to South Korea in 1983. Another North Korean pilot did the same in 1996. China’s official policy is to return North Korean defectors, though in practice it allows many to stay quietly.