North Korean leader Kim Jong-Il returned Friday from China full of praise for his country's key ally, but analysts saw few signs of firm agreement with Beijing on economic reform or denuclearisation.

Kim was greeted by his son and heir apparent Jong-Un and senior officials after his armoured train crossed the border early Friday following a 6,000-kilometre (3,720-mile) trip, the North's official Korean Central News Agency (KCNA) said.

Kim, making his third trip in just over a year to his impoverished nation's economic prop, visited the northeast and east as well as Beijing, where he met President Hu Jintao and other top officials.

China has pressed its wayward ally to return to six-nation nuclear disarmament talks and ease tensions with South Korea. It also calls for a Chinese-style opening-up of the crumbling state-directed economy.

Kim praised China's "dynamic progress" and Hu's warm hospitality but analysts saw little apparent agreement on either nuclear or economic issues.

Official media in Pyongyang and Beijing put different glosses on Kim's talks with Hu on Wednesday.

China's Xinhua news agency said that Kim called for a quick resumption of the long-stalled disarmament talks, and expressed hope for better ties with South Korea.

KCNA said only that the two leaders agreed that denuclearisation "on the whole Korean peninsula" was in the region's interests.

It should be achieved through dialogue including the resumption of six-party talks "and the elimination of obstructive elements", the agency added without specifying the elements.

The North has repeatedly expressed conditional willingness to return to the talks it quit two years ago. But icy relations with the South, following two deadly border incidents blamed on the North, are complicating the issue.

Kim Yong-Hyun, of Seoul's Dongguk University, said there was no strong hint that the North would give up its nuclear weapons.

"Given its current economic situation, it's also difficult for North Korea to accept China's request for openness and reforms," he added.

China's Premier Wen Jiabao had said Kim was invited to study China's dramatic economic development in the hope he would use the knowledge to revive his own country's economy.

But analysts said Kim's regime fears the loss of political control that such reforms would entail, especially given the planning for an eventual succession to a young and untested leader.

A senior Seoul official, speaking on condition of anonymity, said Kim's trip was partly intended to secure support for the succession plan.

"To win economic assistance from China, Kim might have given his commitment to denuclearisation, but there was a gap between the two sides over economic reforms," Yang Moo-Jin of Seoul's University of North Korean Studies told AFP.

South Korea played down the Beijing summit.

"We don't pay any particular attention to what Chairman Kim Jong-Il said," said Foreign Minister Kim Sung-Hwan, adding that Seoul is waiting for an answer to its earlier proposal for inter-Korean nuclear talks.

The minister said China may increase investment in the North's Rason free economic zone but not on the scale that the North wants.

Seoul's unification ministry urged Pyongyang to demonstrate its commitment to denuclearisation "not through words, but through action".

The South's Yonhap news agency said two planned groundbreaking ceremonies to mark China's additional investment in North Korea were abruptly cancelled.

It said one was related to a joint project to turn Hwanggumpyong, an island in the Yalu River near the border city of Sinuiju, into an industrial complex, and another was a ceremony at Rason.