Kim Jong-il arrives in China via armored train

Kim Jong-il has arrived in China on a 17-carriage armored train on a trip to his country's sole major ally that could lead to the revival of stalled nuclear talks.

It is Kim's first trip in more than four years to China, the North's main source of finance, food and fuel and which is seen as one of the few nations able to put pressure on Pyongyang's hardline regime.

Kim, who is said to dislike air travel, has visited China four times since 2000 by train. The last trip in January 2006 was shrouded in secrecy and only formally announced after it had ended.

The visit comes after Chinese president Hu Jintao met South Korean president Lee Myung-Bak on Friday and also held talks with North Korea's number two leader Kim Yong-Nam on the sidelines of the World Expo in Shanghai.

Kim is expected to meet Chinese President Hu Jintao to discuss economic assistance and the North's return to the six-party nuclear talks. It remains to be seen whether they will discuss the sinking of the South Korean Navy corvette Cheonan and whether Kim Jong-un, Kim's son and heir apparent, accompanies him.

Another government official said, "We assume that Kim decided to visit China before the ongoing investigation of the Cheonan sinking is released."