Kim Jong-il and his armoured train arrived in Russia over the weekend to begin a trip shrouded in secrecy, during which he is expected to meet Russia's President Dmitry Medvedev.
The North Korean leader will travel thousands of miles on the specially equipped train, and yesterday made a brief stop to tour a hydroelectric plant.
Photographers from Russian media outlets have been banned from taking any pictures of the train, and no official timetable of the Korean leader's movements has been released.
Unconfirmed reports suggest the two leaders will meet tomorrow in the Siberian city of Ulan Ude, nearly 2,000 miles along the Trans-Siberian railway from the border with North Korea.
It is unknown if Mr Kim will also meet with Prime Minister Vladimir Putin.
The North Korean leader has a fear of flying. He visited China in May but it is his first trip to Russia since 2002, when he took a brief train ride to the east of the country for talks with Mr Putin, then the president.
On the agenda for the Russian leadership this time will be the stalled talks over North Korea's nuclear programme, and possibly also the construction of a pipeline that will send Russian natural gas to South Korea, via the North.
The project would provide much-needed energy to South Korea and potentially earn the North much-needed revenue from transit fees,.
North Korea is believed to be keen to restart talks over the nuclear weapons programme in return for increased aid to avert famine in the country. Russia said last week that it would deliver 50,000 tonnes of wheat to the nation.
It is believed the carriage used for official talks was a gift from Joseph Stalin to Mr Kim's father, Kim il Sung.
A special locomotive travels ahead for extra safety, and the cargo carriage contains two armoured Mercedes.