China has pressed North Korea to speed up economic reforms in a summit encounter that underscored Beijing's concerns about its impoverished and wayward ally, experts said Tuesday.

Many analysts said North Korean leader Kim Jong-Il's five-day tour of northeast China -- which ended Monday -- was aimed at conferring legitimacy on an eventual handover of power to his youngest son.

But for China, reviving the North's moribund economy also appears paramount at a time when it is trying to coax Kim back to nuclear disarmament talks and put a lid on regional tensions that risk perilous instability on its border.

"For China, the most important thing is to step up economic cooperation with North Korea," Jin Jingyi, a Korea expert at Peking University, told AFP after the visit, during which Kim held talks with Chinese President Hu Jintao.

"The political aspects are too sensitive, especially for South Korea and the United States. China doesn't want to see another Cold War in northeast Asia, so right now China thinks it is more important to focus on economic cooperation."

The North Korean leader rarely travels abroad but it was his second visit to China -- Pyongyang's sole ally and economic lifeline -- this year. In May, he visited facilities in and around the Chinese ports of Dalian and Tianjin.

During a visit to Pyongyang last October, Chinese Premier Wen Jiabao proposed the development of a China-North Korean "economic belt".

Chinese state media said a meeting in Changchun on Friday between Kim and Hu focused in large part on economic issues, with Hu again stressing that China was "ready to grow trade and economic cooperation" with Pyongyang.

The Chinese leader reminded Kim that Beijing's stunning economic rise over the past three decades would not have been possible "without cooperating with the outside world", the Xinhua news agency said.

Xu Tiebing, a professor of international relations at the Communication University of China, told AFP: "China has actually all along tried to push North Korea toward economic reform, but the effect of this is not so clear."

Beijing may have "lost hope" as Pyongyang had yet to transform China's advice on reform into concrete action, but would continue to push the North to open up its Stalinist economy, Xu said.

North Korea has in fact ignored its Chinese patrons and taken the opposite course of late, clamping down on putative private markets after a disastrous currency reform last November.

South Korean analysts see even less scope for any economic reform that could loosen the North Korean communist party's iron grip on power, heading into a pivotal meeting next month that could anoint Kim's son as his heir apparent.

Nevertheless, Chinese media flagged up footage of Kim visiting industrial sites and inspecting high-speed trains during his mystery-shrouded tour of several cities.

"This points to North Korea having a strong interest in opening up and developing its economy," the state-run Global Times said in an editorial.

"It is hard to imagine that any country wants to stay poor and isolated. The international community should not marginalise North Korea out of prejudice."

The newspaper said that if North Korea is to focus on economic development, and if tensions in the region are to be eased, the United States, Japan and South Korea should not "bully" Pyongyang.

On Monday, the United States slapped new sanctions on the North in the form of asset freezes and travel bans, stepping up the pressure after the sinking of a South Korean navy ship in March which was blamed on Pyongyang.

Kim reportedly told Hu that his nation was willing to return to long-stalled nuclear disarmament talks and reduce tensions, but experts said the standoff was made even more complicated by the vessel's sinking.

"North Korea has all along said that it is willing to return to the six-party talks, but it is not enough for North Korea to say this for the talks to restart. The key is South Korea and the United States," Jin said.