A special train carrying North Korean leader Kim Jong-un has been spotted passing through a central Chinese province on Monday as it was heading to Vietnam for the second North Korea-U.S. summit. 

According to popular social media site Weibo, China's Twitter, a train presumed to be Kim’s was seen arriving in Changsha in Hunan Province at around 1:10 p.m. before leaving there soon afterwards. Earlier, the train stopped at Dandong, China’s border city with North Korea. 

The train departed from Pyongyang at around 5 p.m. on Saturday, Korea time, and is believed to have taken a route linking China’s inland cities, including Tianjin, Zhengzhou and Wuhan. 

It is expected to travel through Nanning and Pingxiang and arrive in Hanoi on Tuesday morning. Security measures were being augmented around Pingxiang located near Vietnam as of Monday afternoon.