North Korean leader Kim Jong Il, who rarely travels abroad, made an unusual third trip in just over a year Friday to his country's main ally and benefactor, China, news agencies reported.

The trip set off a media frenzy because many initially reported it was his son and heir apparent, Kim Jong Un, who had crossed the border — a reflection of the difficulty of getting information from or about North Korea.

Later, South Korea's Yonhap News agency and others, citing anonymous government sources, backtracked and said they now believed it was the father. It's not clear whether the younger Kim is with him. The South Korean government couldn't confirm reports of a visit by either Kim.

The reported trip comes as North Korea struggles to feed its population and faces increasing pressure from the international community to end its nuclear weapons program. Kim could be seeking support from China for these problems.

North Korean state media made no mention of any state visit to China, and China's Foreign Ministry and the Communist Party leadership office that handles relations with North Korea told The Associated Press they didn't know anything about a Kim Jong Un visit. In the past, China has only confirmed such visits after they're done. Kim Jong Il visited China in May and August of last year.

Despite the confusion in Seoul, there were signs that a high-profile visitor was in China.

In Mudanjiang, a northeastern Chinese city near the North Korean border that the senior Kim visited last year, security was high along the streets, the director of the main office of the city's Beishan Park, told the AP. He gave only his surname Liu.

He said provincial Chinese leaders converged Thursday night at a government guesthouse known locally as the VIP Building, where visiting dignitaries are entertained.

The Jingbo Lake Hotel was closed down Thursday night and its customers ordered to leave, according to a woman who was part of a skeleton staff remaining. The security measures were lifted mid-afternoon Friday, she said, but she did not know if any North Korean dignitaries had visited the lake.

Kim Jong Un, who is in his late 20s, made his international public debut in October last year after being promoted weeks earlier to four-star general and receiving the position of vice chairman of the ruling Workers' Party of Korea's central military commission.

A trip by the young man to China would seem to be looming, as Beijing provides a tremendous amount of material and diplomatic to support to the struggling North Korea, shunned by many in the international community. When a high-ranking Chinese official visited the North last year, a photo of the official with both Kims was taken as a sign that Beijing was acknowledging and maybe endorsing the plan.

The elder Kim, 69, who himself inherited power from his father, reportedly suffered a stroke in 2008. He appears to have recovered and has resumed his steady round of visits to factories and farms around the country.


Associated Press writers Kay Seok and So Yeon Kwon in Seoul and researchers Zhao Liang and Yu Bing in Beijing contributed to this report.