A South Korean newspaper reported Wednesday that Seoul obtained intelligence that a special North Korean train has crossed into China, but that it was unclear whether leader Kim Jong Il was aboard.

The Dong-a Ilbo newspaper quoted government officials as saying that the U.S. or Russia confirmed through satellite images that the North Korean train was traveling in China. The origin of the information was unclear.

The officials were quoted as saying that it was uncertain whether the train was carrying the North's reclusive leader.

CountryWatch: North Korea

Foreign Ministry spokesman Choo Kyu-ho said he couldn't confirm the report and the government had no credible information. Japan's Chief Cabinet Secretary Shinzo Abe told reporters in Tokyo on Wednesday that the government as yet had no confirmation that Kim had begun such a trip.

China's Foreign Ministry had no immediate comment. Calls to the North Korean Embassy in Beijing went unanswered.

Last week, a South Korean Internet news site specializing in North Korea reported that Kim may visit China this week. The South's largest newspaper, Chosun Ilbo, carried a similar report.

Kim rarely travels abroad, but has occasionally visited allies China or Russia, last traveling on a tour through several Chinese cities in January. Beijing and Pyongyang didn't officially acknowledge Kim had been in the country until after he left.

The reports came amid growing concern that the North might be preparing to test a nuclear bomb.

North Korea has claimed it has nuclear weapons, but hasn't performed any known test.

The North has stayed away from six-nation talks on its nuclear program since November in anger over the U.S. blacklisting a bank where the Pyongyang regime held accounts due to its alleged complicity in counterfeiting and money laundering.