North Korean leader Kim Jong-il has reportedly crossed the Yalu River on a visit to China aboard a special train.

Quoting a South Korean intelligence official, the Donga Ilbo daily in Seoul said Wednesday that Kim’s train traveling in China was spotted by U.S. or Russian satellites.

The train is known to be the one that Kim used on his previous visit to China in January, but it is uncertain whether the train was carrying Kim this time.

A Unification Ministry official in Seoul said that the government has not confirmed the information, adding that intelligence agencies are in the process of verifying the report.

In Beijing, the South Korean Embassy also said that China has yet to confirm anything despite rumors of Kim's visit.