North Korean leader Kim Jong-Il visited a development zone in eastern China on Monday, media reports said, as he pursued a secretive trip aimed at seeking answers for his nation's crippled economy.

Kim, on his third visit to China in just over a year, toured the economic development zone in Yangzhou city near the industrial hub Shanghai, South Korea's Yonhap new agency said, citing unnamed sources.

North Korea watchers believe the latest trip by a man who rarely leaves his country reflects a dire need for help with severe economic problems and food shortages amid ongoing international sanctions over its nuclear ambitions.

Chinese Premier Wen Jiabao confirmed Kim's visit for the first time on Sunday, telling South Korean President Lee Myung-Bak in Tokyo that Kim wanted to study China's vibrant economy, according to a Seoul official.

Kim may also visit the site of a joint industrial park on North Korea's border with China on the way home, Yonhap said.

That would likely underscore a commitment to further economic cooperation with China, impoverished North Korea's closest ally and main benefactor, Yonhap said.

The reclusive, frizzy-haired Stalinist ruler has traversed much of eastern China aboard his personal train and the trip also is widely viewed as intended to show he is healthy and firmly in charge.

Kim, 69, suffered a stroke in 2008 and has launched a succession plan involving his youngest son and heir apparent Kim Jong-Un. It was not immediately clear if his son was part of his entourage in China.

His arrival in China on Friday came just ahead of a weekend summit in Tokyo between China, South Korea and Japan, which agreed North Korea must show sincerity before stalled six-nation talks on its nuclear programme can resume.

A spokeswoman with China's ruling Communist Party confirmed to AFP on Monday that Kim was still in the country but declined to provide further details.

"The leader of North Korea, Kim Jong-Il, is currently visiting China," said the spokeswoman with a party department handling international relations, who declined to provide her name.

Details of Kim's visits are typically divulged by both sides only after he has returned home, but Yonhap said the trip was expected to last a week.

Yonhap said Kim arrived in Yangzhou in Jiangsu province on Sunday after at least two stops in China's northeast.

A motorcade believed to be transporting Kim departed from a government-run guest house in the city Monday morning, it quoted sources as saying.

South Korea's JoongAng Ilbo newspaper said Kim went to Yangzhou for a Sunday meeting with former Chinese president Jiang Zemin -- who met Kim's late father and North Korean founder Kim Il-Sung there in 1991.

Kim also may be planning a visit to nearby Shanghai, with a later stop in Beijing to meet with Chinese President Hu Jintao, it said.

While in Yangzhou, Kim may have met with Vice President Xi Jinping, who is expected to become China's president in 2013 when Hu steps down, Yonhap said.

Guest house staff in Yangzhou told AFP it was accepting no reservations until Tuesday, but declined to confirm Kim was there.

The city government also stayed silent but postings on Twitter-like Chinese microblogging services by users in Yangzhou reported a heavy security presence shutting down major roads, possibly to accommodate Kim's motorcade.

During the previous visit last August, Hu urged Kim to open up his country's state-directed economy.

Kim's regime introduced limited reforms in 2002 but later rolled back most of them, apparently fearing a possible loss of political control.

The economy remains crippled by severe shortages of power, raw materials, and persistent food shortages.

Yonhap said North Korea and China will break ground later this week on a joint project to turn Hwanggumpyong, an island in the Yalu River on their border, into an industrial complex, and quoted sources saying Kim may attend.

Overseas aid for North Korea is waning because of anger at its nuclear and missile development. International sanctions have been imposed to try to curb those programmes.

Six-party talks aimed at scrapping the nuclear programme in exchange for diplomatic and economic benefits have been stalled for more than two years.