North Korea's leader, Kim Jong-il – who is known for shunning air travel – has six luxurious trains equipped with reception halls, conference rooms and hi-tech communication facilities, according to a Seoul newspaper.

There are also 19 stations across North Korea that exclusively serve his trains, which have a total of some 90 carriages, the Chosun Ilbo reported, citing an analysis by South Korean and US intelligence services.

It said the information was obtained via US spy satellites, reconnaissance aircraft and the testimonies of North Korean defectors. But South Korea's National Intelligence Service and the US military command in Seoul said they were unable to confirm the report.

The paper said Kim uses the trains when he visits army units and factories or travels abroad and that each armoured train has modern communications equipment, such as satellite phones, enabling the leader to obtain briefings and issue orders while travelling.

Kim's train travels at less than breakneck speed, said the paper, usually 37mph (60 kph).

To cope with any attempts to harm the North Korean leader, his train travels between two others, with the first running ahead to check the safety of railway lines and the second to carry a retinue of security agents and followers, Chosun Ilbo said.

The paper quoted an unidentified source as saying security measures on the trains were boosted after an explosion in 2004 that killed about 160 people and injured 1,300 others.

The blast in Ryongchon, near the border with China, was believed to have been caused by a train laden with oil and chemicals hitting power lines.

But the explosion occurred hours after Kim reportedly passed through the station on his way home from a three-day visit to China, sparking speculation it might have been an assassination attempt.

The reclusive leader rarely travels abroad – and only under tight security – and avoids flying. He last visited China in 2006, though state media recently reported that the Chinese president, Hu Jintao, has invited him to visit again.

It's not clear when or even if the 67-year-old Kim, who reportedly suffered a stroke last year, will accept the invitation.