North Korea's leader Kim Jong-Il on Wednesday promised President Dmitry Medvedev in rare talks that his reclusive state was prepared to renounce nuclear testing and allow transit of a key gas pipeline.

The meeting followed Kim's four-day train ride through Russia's Far East and Siberia -- his third visit to the giant neighbour in the last decade but the first since 2002.

The secretive Kim made no comment to reporters after the meeting outside the Siberian city of Ulan-Ude some 5,550 kilometres (3,450 miles) east of Moscow, but Medvedev expressed satisfaction with the outcome.

"I am full of positive feelings. The meeting was substantive and open," Medvedev said.

He told journalists that the Stalinist state supported a planned pipeline to carry Russian gas supplies to South Korea through the North, a route that would allow Moscow to reach new energy-hungry Asian markets.

The deal would concern "the transit of gas across the territory of North Korea and accordingly the addition to this project of the Republic of Korea, considering that the main consumers are on its territory," Medvedev said.

Kim left Russia later Wednesday and was seen off by Medvedev, the KCNA news agency reported.

After a long-lasting freeze in six-party talks on the North Korean nuclear programme, a Kremlin official said Pyongyang was ready to impose a moratorium on nuclear testing and processing if the discussions resume.

"Without preconditions, in the course of the negotiations, the North Koreans will be ready to solve the issue of introducing a moratorium on testing and spent nuclear fuel processing," Kremlin spokeswoman Natalya Timakova told reporters.

North Korea has previously called for an early resumption of six-party talks involving China, Japan and the United States as well as the two Koreas and Russia, "without preconditions".

But the South insists its neighbour must first suspend all atomic activities and the US State Department called the reported offer "welcome but ... insufficient".

"If it's true, (it's a) welcome first step, but far from enough ... to resume the six-party talks," State Department spokeswoman Victoria Nuland told reporters.

Pyongyang stormed out of the six-party negotiations in April 2009 and conducted its second nuclear test a month later.

Kim earlier swept up to the meeting at the Sosnovy Bor (Pine Forest) garrison outside Ulan-Ude in a 1990s black Mercedes with no number plates.

He was welcomed by Medvedev, whose business suit and bright violet tie creating a glaring contrast with the dull khaki uniform of the North Korean supremo.

The two men sat at a small table decorated with white flowers, backed by the flags of the two nations. They were later joined by their delegations for full negotiations.

Kim had arrived in Ulan-Ude aboard his armoured train a day earlier after a week-long Trans-Siberian journey which started at the weekend when he crossed the border into Russia's Far East.

His journey has seen him enjoy varied excursions including a dip in Siberian waters, touring a plant making assault aircraft, taking a trip on the famed Lake Baikal, eating local fish and visiting a hydro-power station.

"I hope that you have been able to see what you wanted to," said Medvedev. Kim replied: "Thank you for the great attention from your side, Mr President, we are having a very fun journey."

Locals however were far from amused, complaining of disruptions to their daily routine because of the summit.

"Everything was turned on its head," an employee at the Ulan Ude rail station, where the 69-year-old Kim had earlier parked his train, told AFP.

"Nobody was allowed near the train, the station was surrounded. We had to be led to work by our boss."

Kim last travelled to Russia in 2002 when he met then-president Vladimir Putin in Vladivostok. In May, Kim visited China, the third trip in just over a year to his country's major ally and economic lifeline.