The summit between North Korea's Kim Jong-Il and President Dmitry Medvedev is set to take place on Wednesday in the eastern Siberian city of Ulan-Ude, a person familiar with the plan told AFP.
"The guest is arriving tomorrow," the person, who refused to go on the record because of the sensitivity of the situation, said on Monday.
"Our (leader) will be there Wednesday," he said.
The talks will take place in the eastern Siberian city of Ulan-Ude near Lake Baikal in the Buddhist region of Buryatia, 5,550 kilometres (3,450 miles) east of Moscow, he said.
Kim will also be shown around the picturesque shores of Lake Baikal and offered a boat ride, the person said.
He did not provide further details, saying he had given a written pledge not to disclose this information.
South Korea's Yonhap news agency cited a Seoul-based senior government official as saying: "There is a possibility that Kim will arrive in Ulan-Ude on Aug. 23 and hold the summit on Aug. 24 after spending a night."
In an apparent nod to Kim's concerns about personal safety, the Kremlin imposed a virtual blanket ban on information about the plans and itinerary of the 69-year-old leader, now rumbling across the Trans-Siberian railway aboard his special armoured train.
The Kremlin said in a terse statement that the summit will be the highlight of the reclusive Kim's week-long tour of Russia's Far East and Siberia, his second visit to the giant neighbour since 2002.
Monday was the third day of Kim's week-long trek, a rare trip out of his country battling food shortages and isolation.
"The special train carrying the general secretary of the Workers' Party of Korea and chairman of the National Defence Commission of the Democratic People's Republic of Korea is going along the Trans-Siberian railway in the direction of Ulan-Ude," the administration of the Buryatia region said.
"Vladivostok, Khabarovsk, the Amur region have been left behind, and Chita is now the next big city along the Transsib railway," it said in a statement on its website quoting the ITAR-TASS news agency.
A spokesman for the Buryatia regional authorities said he could not provide details of Kim's plans in the region.
"Everything is being kept secret," he said.
The Kremlin announced the high-profile visit several hours after Kim's armoured train crossed the border into Russia on Saturday.
On Sunday he visited the 2,000 megawatt-strong Bureiskaya hydro-power station in the Amur region, the largest in the Far East.
