Photo taken in August 2010 in China shows a special train used by the then North Korean leader Kim Jong Il. (Kyodo via AP Images)

Video footage circulating online of a 21-car train similar to the one used by North Korean leader Kim Jong Un’s late father has spurred speculation that the secretive leader is in Beijing for a surprise meeting with Chinese officials.

Kim’s visit Monday, if confirmed, would mark the young leader’s first trip outside North Korea since taking over the reins from his father in 2011, and comes just weeks before he is due to meet South Korean President Moon Jae-in for the first time. The two are expected to discuss Pyongyang's nuclear weapons program and an unprecedented and still undetermined meeting with President Trump.

The surprise visit and its timing would be “pretty significant,” Melissa R. Hanham, a senior research associate at James Martin Center for Nonproliferation Studies, told VICE News.

Though China remains North Korea's most valuable trading partner that enjoys some sway with Kim Jong Un, Beijing's relationship with the hermit kingdom is "pretty bad," said Hanham. The relationship between the two countries has soured in recent years because of North Korea’s aggressive push for nuclear weapons and Beijing’s backing of sanctions.

Hanham said China is interested in maintaining the status quo in the region and would likely dodge a photo op with Kim to avoid the perception of the two countries as equal partners.

Hanham added that Kim, who unlike his father enjoys flying, might’ve opted for the train as a way to “invoke the memory of his father.”

Japanese TV caught footage of the olive-green train with two gold stripes and a white roof, reporting it was possible that high-level North Korean officials were on board.

Beijing Railways, which offers trains to and from North Korea’s capital, has confirmed multiple delays, according to the New York Times’ Asia Editor, Phillip Pan.

Video of a heavily secured motorcade driving through the streets of Beijing from the train station also surfaced to bolster rumors.

South Korea is “thoroughly monitoring the situation” and is “closely communicating” with China, a foreign ministry spokesman told CNN, without saying who was on the train or why it was there.

It is still unclear what spurred the rumored visit and whether it had anything to do with President Trump or newly appointed national security adviser John Bolton, who just last month advocated for war with North Korea.

During a press briefing Monday, the White House declined to confirm if the reports were true or if the U.S. was aware of the visit beforehand, and VICE News could not independently confirm Kim’s visit. When asked for comment, State Department spokesperson Julia Mason told Bloomberg, “We’d refer you to the Chinese.”

Such confusion is hardly a new phenomenon when it comes to North Korea.

“As usual, there’s way more guessing going on than actual information,” Hanham said.