North Korea's leader Kim Jong-il has held rare talks with Russian President Dmitry Medvedev on Pyongyang's nuclear programme and economic co-operation.

朝鲜领导人金正日与俄罗斯总统就平壤核计划和经济合作问题与俄罗斯总统梅德韦杰夫举行会谈。

Mr Kim said his country was ready to discuss ending nuclear tests if six-party talks on denuclearisation resumed, Russian media reported.

The pair also discussed plans for a pipeline¹ that would pass through the North's territory to South Korea.

There has been no official comment so far from North Korea.

The Russian gas company, Gazprom, has reportedly been working for years on the deal for the pipeline, which would stretch more than 1,700km (1,000 miles).

South Korean media reports that the deal could be worth up to $100m (£60m) annually² in transit³ handling fees（手续费） for the impoverished⁴（贫穷的） North.

But the BBC's Lucy Williamson in Seoul says it would also give Pyongyang de facto control（实际控制权） over a key energy supply to the South, and without a major step forward in relations on the peninsula, that is likely to make some in Seoul very nervous.

Key ally

The meeting between the two leaders took place at a military base, near Siberia's eastern mountains, some 5,550km (3,450 miles) east of Moscow.

It is Mr Kim's first visit to Russia since 2002.

Photographs showed the two leaders sitting together looking jovial⁵ and relaxed; Mr Kim smiling openly in his trademark⁶ beige（米黄色） suit, and Mr Medvedev leaning in to him with a smile.

A spokesman for the Russian president described the talks as "frank and substantial".

"Kim Jong-il expressed readiness to return to six-party talks without preconditions," said Mr Medvedev's spokeswoman, Natalya Timakova.

"In the course of the talks the North Koreans will be ready to resolve the issue of imposing⁷ a moratorium⁸ on testing and production of missile and nuclear weaponry."

The meeting in Russia follows weeks of new discussions between North Korea's nuclear envoy⁹ and his South Korean and US counterparts over how to return to formal negotiations¹⁰ on the North's nuclear programme.

In 2009, Pyongyang walked out of six-party talks with South Korea, the US, Japan, China and Russia, and conducted its second nuclear test soon after.

The meeting was also a chance to discuss economic ties between North Korea and its eastern neighbour.

North Korea has been increasingly vocal¹¹ about its need for aid and investment to prop¹² up its ailing¹³ economy.

With speculation¹⁴ that Mr Kim returned disappointed from his recent trips to China, analysts¹⁵ are wondering whether the reclusive leader is looking to his other key ally for help, our correspondent says.

On the eve of Mr Kim's visit, Moscow announced it was providing 50,000 tons of wheat to Pyongyang.

Mr Kim arrived in his armoured train in the border town of Khasan in the Russian Far East on Saturday.

The itinerary¹⁶（路线，旅程） for his visit, which is expected to last about a week, has largely been kept secret because of Mr Kim's concerns for his personal safety.

During his first few days in Russia, Mr Kim is reported to have visited a dam north of Vladivostock, taken a swim in the waters of Lake Baikal, and toured a Soviet-era aviation plant.