North Korean leader Kim Jong-il arrived aboard his armoured train in a Siberian city on Tuesday for talks with Russian President Dmitry Medvedev likely to cover Pyongyang's nuclear programme and aid for his destitute nation.
Russian and South Korean officials confirmed Kim's train had reached Ulan-Ude, three days after crossing the border more than 2,000 km (1,250 miles) to the east.
Neither side has announced a date or location for Medvedev's meeting with Kim, who leads one of the world's most secretive nations and is on his first visit to Russia in nine years. However, it is widely expected to be held on Wednesday in or near Ulan-Ude, a provincial capital near Lake Baikal.
Medvedev was in the Black Sea resort of Sochi on Tuesday, five time zones to the west.
Media reports say Kim, 69, who travels by train because of his fear of flying, aborted a trip to Russia in June because of security concerns after news of his plans leaked out.
His first visit to North Korea's Soviet-era ally since 2002 caps a relative flurry of diplomacy for the reclusive leader, who has visited China, now his country's closest partner, three times in less than two years.
It also follows discussions between Pyongyang and Washington on the resumption of six-nation talks designed to provide North Korea with economic aid as an incentive for giving up its nuclear weapons programme. .
Russia and China have backed the immediate resumption of the aid-for-disarmament talks which collapsed two years ago and Kim may ask Russia to exert more pressure on South Korea, the United States and Japan to restart the negotiations.
North Korea has also sought economic help from regional powers following floods that have exacerbated problems coping with international economic sanctions imposed because of its weapons programme.
Citing a "severe deficit" of food products, Russia said on Friday it would send 50,000 tonnes of grain to North Korea by the end of September. The North has also been seeking foreign investment to improve infrastructure.
Kim could also seek energy aid, although a long-discussed project for a natural gas pipeline linking Russia with North and South Korea is unlikely to go far without a significant thaw between the two Koreas, which are technically still at war.