Questions and concerns over the aim of North Korea leader Kim Jong-il's reported visit to China mounted over the weekend with elaborate media reports that tracked his unconfirmed journey.

Kim was thought to be heading home Saturday night, when various media outlets said his special train left Changchun, the capital city of Northeast China's Jilin Province. But South Korean media said there was no sign of the train entering North Korea Sunday morning via the Chinese border cities of Dandong or Ji'an, the two most likely gateways.

This led to speculation that Kim was heading toward a third destination in China after his surprise visit to reportedly meet with high-ranking Chinese officials.

Yonhap reported that Kim was believed to have then traveled to China's border cities of Yanji or Tumen.

The Yonhap News Agency cited an unidentified diplomatic source in Yanji, capital of China's Yanbian Korean Autonomous Prefecture, as saying that Yanbian's local government was busy preparing to receive a visitor likely to be Kim.

Yonhap said a visit by Kim to Yanbian would be a sign that there has been development in the economic-cooperation talks between the two countries.

The South's cable news channel YTN also reported that Tumen began cleaning up major streets and restricting traffic Sunday morning.

Neither China nor North Korea have made Kim's visit public. The visit was Kim's sixth trip to China and his second in about three months. He met with Chinese President Hu Jintao during his previous visit in May.

The Associated Press quoted a duty officer with the press office of the Chinese Foreign Ministry as saying, "China and North Korea consistently maintain high-level contacts. We will release the relevant information in good time," when the officer was asked whether Kim was visiting China.