BEIJING - China pledged to strengthen bonds with isolated North Korea, nudging it to improve its economy, while reports of Indian and South Korean swoops on North Korean shipping underscored strains behind a recent easing of tension.

The renewed courting between the two communist neighbors came in messages between Chinese President Hu Jintao and North Korea's top leader, Kim Jong-il, who on Sunday hugged Chinese Premier Wen Jiabao at the start of a visit intended to bolster bilateral relations.

The messages marked 60 years since the countries established formal ties on October 6, 1949, and did not mention of the North's nuclear weapons program, instead stressing their focus on shoring up ties.

History demonstrates that developing China-North Korea relations is in keeping with the fundamental interests and shared wishes of both countries' people, said the congratulatory message from China, issued by the official Xinhua news agency. It also benefits protecting regional peace and stability.

In a message to China, Kim Jong-il and other North Korean leaders said relations would constantly consolidate and develop, Xinhua reported.

The relationship between the world's third-biggest economy and its impoverished, isolated neighbor sets apart Beijing's approach to Pyongyang from the harder line long favoured by Washington, Tokyo and other regional capitals.

Other governments have pushed China to use its crucial energy and food supplies to the North to press Pyongyang to curb nuclear weapons development. Beijing has been angered by Pyongyang's nuclear threats, but said repeatedly that sanctions will not work and that only renewed negotiations can bring progress.

Analysts said Wen's visit was unlikely to yield more than opaque promises from Pyongyang on the nuclear dispute.

I think the chances of real progress are small, said Zhang Liangui, an expert on North Korea at the Central Party School, an influential state institute in Beijing.

Through visits like this, North Korea is mostly trying to create the impression that other countries respect and heed it, that it's a world power. Of course, that's not true, but the impression helps its leader bolster his authority.

Pyongyang has sometimes appeared prickly about the size and influence of its much bigger neighbor, which has backed U.N. resolutions condemning North Korea's nuclear tests.

But Kim made a rare appearance to greet Wen at the start of his trip, showing how serious is about ties with China. Kim is widely believed to have suffered a serious illness last year.

On Monday, Wen met North Korea's nominal No. 2 leader, Kim Yong-nam, president of the Presidium of the Supreme People's Assembly, and nudged the North to improve its struggling economy.

China and North Korea both face the important tasks of developing their economies and improving the livelihoods of their people, and we must continue strengthening friendly cooperation, Wen told Kim Yong-nam, according to Xinhua.

WHERE NEXT FOR NUCLEAR NEGOTIATIONS?

Fresh reports on detention of North Korean sea traffic served as a reminder that the country remains shunned by most of its neighbors and under international sanctions that Beijing endorsed.
South Korea's Dong-a Ilbo newspaper reported on Monday that South Korean authorities had seized four cargo containers belonging to North Korea under U.N. sanctions imposed in response to its missile and nuclear tests.

The reported seizure of the North's cargo would be the first by Seoul under a U.N. resolution in June. South Korea's spy agency and maritime police made no comment on the report.

Indian warships detained a North Korean cargo ship on Friday for dropping anchor in Indian waters without permission. An Indian navy spokesman said nothing incriminating was found.

Despite the rousing welcome in Pyongyang for Wen, the two sides appear divided over the future of six-party nuclear disarmament talks Beijing has hosted since 2003.

China wants North Korea to return to the intermittent talks, an important platform for Beijing to show its diplomatic prowess.

The talks among the two Koreas, China, Japan, Russia and the United States ground to a halt about a year ago, with Pyongyang saying it would no longer attend the negotiations aimed at curtailing its nuclear weapons capability in return for aid.

North Korea's Premier Kim Yong-Il -- no relation to his supreme leader -- told Wen that Pyongyang was open to bilateral or multilateral talks on nuclear weapons. But in keeping with recent statements by other North Korean officials, Premier Kim did not expressly endorse the six-party talks.

North Korea is much more interested in bilateral talks with the United States, or some multilateral format that excludes Japan, even maybe China. said Zhang. That's an important point of division for the visit, he said of Wen's trip.

(Editing by Jonathan Thatcher and Ron Popeski)

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