Kim Jong-il has travelled by armoured train to eastern Siberia for a summit with the Russian president, Dmitry Medvedev.
The North Korean leader arrived in Ulan-Ude, the capital of Buryatia, a Buddhist province near Lake Baikal, Russian news agencies reported. Kim's motorcade left town in the direction of Turka, a picturesque village on the shores of Baikal.
The Yonhap news agency said the Medvedev-Kim summit was expected to take place on Wednesday.
The talks could focus on a deal for a pipeline that would stream Russian natural gas through the North's territory to the South. South Korean media said the North could earn up to $100m a year.
There were signs that preparations were being made for Kim to visit Turka. The Baikal Daily website quoted residents as saying that a local police officer had been making the rounds to record the names and addresses of all the people in the village.
The visit is shrouded in mystery. A few people managed to take photos of Kim at his previous stop on Sunday, but heavy police cordons kept the press in Ulan-Ude out of the train station.
Kim's train crossed into Russia on Saturday morning and passed through Khabarovsk before heading west along a railway running roughly parallel with Russia's borders with China and Mongolia.
It is Kim's first visit to Russia in nine years. North Korea is also pushing to restart six-nation nuclear disarmament talks in exchange for aid, after more than a year of tension during which it shelled a South Korean border island and allegedly torpedoed a South Korean warship.
Russian military officials arrived in the North Korean capital, Pyongyang, on Monday for a five-day visit. The Russian defence ministry said the talks would focus on the renewal of military co-operation between the countries, possible joint exercises "of a humanitarian nature" and an exchange of friendly visits by Russian and North Korean ships, the Itar-Tass news agency reported.
The North, which has long experienced chronic food shortages, has been hit with heavy flooding in recent weeks. The Korea Herald newspaper stated bluntly a strain of thinking in Seoul in an editorial on Tuesday: "It does not take genius to guess why Kim is visiting Russia. [He] desperately needs economic aid."
