Unconfirmed reports: Kim Jong-un makes surprise visit to Beijing

North Korean leader Kim Jong-un has conjecturally made a secret visit to Beijing, as an armoured train, accompanied by an unusually heavy security detail, arrived at the Chinese capital on Monday.

According to South China Morning Post, the reports come after a heavy police presence was noted at the border of China and North Korea, and at a Beijing hotel popular with foreign dignitaries.

However, it has not been confirmed yet whether it is, in fact, the North Korean autocrat on board the train, though the security suggests it would be a very high-level official.

There has been a spike in police activity in Beijing recently, especially around the Diaoyutai State Guesthouse, where foreign dignitaries usually stay, with a large number of officers and about 50 vehicles seen in the area. Nearby roads have been cordoned off.

The news has quickly been caught up by the Twitterati, with one user sharing a video of a green, armoured North Korean train, with Kim likely on board, being spotted in Beijing.

"Breaking: North Korean armored train spotted at Beijing, China. Kim Jong Un probably on board," he tweeted.

If the rumours turn out to be true, this would be the first time Kim would have stepped out of North Korean soil since he took power in 2011.

Kim is also supposed to hold meetings with South Korean President Moon Jae-in and United States President Donald Trump, in April and May, respectively, to hold discussions about de-nuclearisation of North Korea.