Mysterious train in Beijing sparks speculation of visit by Kim Jong Un

Mystery train spotted in China

BEIJING -- A mystery train pulled into Beijing on Monday and immediately the word on the street was that it came from North Korea and might be carrying leader Kim Jong Un. If so, it would be Kim's first trip away from home since taking power in 2011.

It was the distinctive green and yellow markings on the train that set off a firestorm of speculation on Chinese social media. Japanese media caught a glimpse of the 21-car train that signified a VIP was on board. In Beijing, it appeared as if an honor guard welcomed the mystery visitor.

Chinese media reported a heavy police presence at a Beijing guest house where foreign leaders often stay. Roads were closed and streets cordoned off, only fueling the idea that Kim had slipped into the Chinese capital. Tourists were cleared off Tiananmen Square, which normally only happens for important meetings.

The speculation comes as delicate negotiations are underway for possible talks between North and South Korea and the U.S. over the North's nuclear program. The last summit between the Koreas was 2011 when Kim's father took an identical train to Beijing just weeks before talks began.

China is North Korea's only ally, accounting for 90 percent of its trade. Kim and Chinese President Xi Jinping have never met.

U.S. State Department officials say all they know is that a high level North Korean delegation appears to be in Beijing. The mystery may continue because when Kim Jong Un's father visited Beijing it was never acknowledged he was there until he was safely back in North Korea.