North Korea's Kim Jong-il on trip to China, reports say

North Korean leader Kim Jong-il was believed to be travelling to Beijing on Thursday on what would be his second visit to the Chinese capital this year, according to South Korean reports.

Intelligence officials can typically detect when the reclusive North Korean leader visits China through movements along the rail lines between Beijing and Pyongyang. Kim does not like to fly, opting instead to travel by rail.

There are also indications that Kim may be accompanied on this trip by his third son and heir apparent, Kim Jong-un.

There has been no comment from the Chinese Foreign Ministry in Beijing, nor from the authorities in Pyonyang, to confirm the presidential visit.

The purpose of Kim’s latest trip to Beijing is not immediately clear. South Korea’s Yonhap news agency quotes various anonymous sources who claim the purpose of the visit may be to discuss Kim’s succession or the resumption of six-party nuclear talks.

Beijing has been stepping up efforts to resume talks on disarming the North amid simmering tensions over the sinking of a South Korean warship in March, for which Pyongyang was blamed.

The president’s reported trip to Beijing comes just one day after former US president Jimmy Carter arrived in Pyongyang on a humanitarian mission to lobby for the release of an American citizen currently detained in North Korea.

Kim last visited China in May and met with Chinese President Hu Jintao.