North Korean leader Kim Jong-il’s days-long trip to China appears to have done little in securing a promise of reliable financial and diplomatic support from the longstanding ally, observers in Seoul said Friday.

A special train carrying Kim and the 70-member entourage left the border region of Dandong Friday morning and is expected to arrive back in Pyongyang later in the day, the South Korean media said, citing sources there.

Kim reportedly arrived in China last Friday, looking around several industrial facilities before heading to Beijing for a meeting with President Hu Jintao Wednesday. The ailing dictator traveled at least 6,000 kilometers across northern and eastern regions of China for the purported “reforms and development learning purposes,” local reports say.

The 69-year-old Pyongyang leader, who rarely travels abroad, was believed to have pleaded for aid and diplomatic backup from his impoverished state’s last-remaining benefactor.

“We are not detecting any signs of a new, concrete agreement made between the two sides,” a Seoul official said, asking not to be named as he was not authorized to represent the government on the issue.

“Reports appear to be focused on reopening the six-party talks at an early date, which are no more than a reaffirmation of what we’ve all been discussing for months,” the official said.

As the first official confirmation of Kim’s much-veiled trip, China’s Xinhua News Agency said Thursday that the North Korean leader had called for “an early resumption” of the multinational talks aimed at its denuclearization.

Hosted by China, the six-nation dialogue, also involving the two Koreas, the U.S., Japan and Russia, has been stalled since the end of 2008, fueling regional concerns over Pyongyang’s ongoing nuclear ambitions.

China has been, for months, trying to get the two Koreas to hold nuclear talks and mend ties as the first step in restarting larger-scale negotiations.

South Korea, which suffered two deadly attacks from the North that killed 50 of its people last year, has been firm not to resume aid or dialogue until a proper apology is offered. Pyongyang continues to deny responsibility.

A following report by Pyongyang’s Korean Central News Agency said the two leaders had agreed on the “need of a peaceful solution to the nuclear standoff,” but neither side mentioned much about talks over their purported economic cooperation, hinting at a possible disaccord.

“China is not the China a decade ago,” a diplomatic source close to China said. “It no longer backs North Korea up unconditionally. North Korea has to do its part of the deal.”

Backing such speculation, a groundbreaking ceremony that would have marked additional Chinese investment in North Korea was abruptly canceled as Kim headed back home.

China and North Korea have long been seeking economic cooperation that may include a joint project to turn Hwanggumpyong Island in the Yalu River on their border into an industrial complex.

North Korea has also been hoping for Beijing to make more investments in Rason, a free trade zone it has been striving to develop into a regional transportation hub near China and Russia.

“China has been skeptical about developing the island, believing it will bring little economic outcome,” the diplomatic source said, adding China is seeking to build a massive industrial park in its Dandong region instead.

Beijing’s financial assistance has been growing more vital for Pyongyang since 2008, when it was slapped with strict economic sanctions for conducting a second atomic test.

China, Pyongyang’s sole benefactor, has often played the role of mediator between the unpredictable state and regional powers including the U.S. and South Korea, keen to prevent changes that might occur in the case of the Kim regime’s collapse. Although North Korea often causes it a headache, being Pyongyang’s sole ally gives Beijing the upper hand over the U.S. in issues related to regional security and economy.

The fact that Kim visited China three times in just over a year indicates the dictator’s growing urgency for its financial support, especially as he prepares to hand over the impoverished regime to his young and inexperienced son.

Beijing, meanwhile, appears to be turning somewhat difficult, refusing to do Pyongyang any favors unless it offers something in return. China wants, among other things, North Korea to open up and reform its ailing economy, mend ties with Seoul and rejoin the denuclearization talks.

By Shin Hae-in (hayney@heraldcorp.com)