"Asia has increasingly become prominent in the world's political, security and commercial affairs and so too has it become an increasing factor in the world of proliferation, unfortunately," said Assistant Secretary of State for Non-Proliferation Robert Einhorn.

Addressing a meeting here of the Asia Society think tank, Einhorn outlined the challenges facing the US as it tries to stem the spread of weapons of mass destruction and their missile delivery systems in Asia.

Statistically Asian nations are acquiring more arms, both conventional and nuclear, he said, highlighting the dramatic rise in military expenditure in South Asia and the Korean peninsula.

"One way to alleviate this is to address the underlying political problems that give rise to the desire to acquire more arms" through dialogue, he said.

Einhorn outlined his hope that a seeming relaxation in cross-strait tensions and improved dialogue between China and Taiwan could alleviate the region's perceived need to acquire more arms.

When questioned over US proposals for a National Missile Defense system to protect it from nuclear and other attacks by "rogue" states, Einhorn vehemently denied it would stimulate a renewed arms race in the region, in particular with China.

"We don't believe there would be a strategic necessity for China to build up its capability beyond that level of modernization it is already undertaking," he said.

But he warned that "China should also know that its own activities will have an impact on the perceptions on the United States ... so China should also look to its own actions as a way for avoiding a missile arms race in Asia."

Einhorn underlined the need for all countries in the region to develop and strengthen export controls which are "a critical tool in the fight against proliferation."

"Asia is the leader in the high-technology field and as a result Asian manufacturing centres and trade hubs are becoming targets of the world's proliferators.

"If Asia is to avoid becoming a supermarket for the world's proliferators then the nations of Asia must work very actively to strengthen their current export control systems," he said.

North Korea, Einhorn said, continued to offer the main threat to the US and its allies in the region in terms of its weapons of mass destruction and through its "indiscriminate sales of missiles and missile technology" to areas from northern Africa to south Asia.

However Einhorn praised North Korea's recent efforts to normalise relations with other countries, referring to recent Pyongyang's recent talks with Japan, Italy, Canada and Australia among others.

"We believe it is very useful for North Korea to expand its contacts in this way. It gives the North increasing incentives to behave responsibly. It knows that if it was to undertake provocative actions that it would put these beneficial relationships at risk," he said.

Just over a week ago North Korean leader Kim Jong II visited Beijing in what appeared to be an effort to mend strained relations between the two neighbours.

Einhorn also highlighted "the challenge of encouraging China to become a more consistently reliable partner in the area of non-proliferation," warning that the US continues to see evidence of the transfer of missile equipment and missile to countries such as Iran and Pakistan.

Referring to the continuing tensions between India and Pakistan, Einhorn warend that the levels of mistrust between the two were dangerously high and the risk of escalation "very real."

He stressed the need for the two South Asian foes to exercise maximum restraint and to resolve their differences peacefully.

Washington's foreign policy establishment is alive with anticipation ahead of the unprecedented talks on June 12-14, with experts debating the impact of a string of possible post-summit scenarios on the United States.

With tens of thousands of troops stationed in South Korea and Japan in support of its regional allies, Washington has a huge stake in the outcome of the talks.

Few analysts dispute that the planned meeting meeting in Pyongyang between South Korean President Kim Dae-Jung and his northern counterpart Kim Jong-Il will be a striking diplomatic showpiece.

They caution however, that it represents only a tiny first step towards a safer Korean peninsula and add that North Korea's motives are shrouded in doubt.

Pyongyang's power politics are so impenetrable that few observers, even a core here who have had close contact with the leadership, can say for sure if North Korea intends to move down a path of reform.

Several possible outcomes of the process started by the Pyongyang summit could turn out to have a direct impact on US policy, said Marcus Noland, senior fellow at the Institute for International Economics.

If Kim Jong-Il decided his Stalinist regime would be strengthened by links to the outside world, he could "pave the way for normalisation (of relations) with the US and ease tensions," Noland said at a seminar here on Korean trade.

In time, and to win US recognition and possible economic aid, North Korea might decide to wean itself off missile production and alleged links with terrorism which currently poison its relations with Washington, he added.

Alternatively, and in a scenario far more dangerous for the United States, North Korea could decide to buy into the "techniques" of the outside world, but not the "values" and ignore the need to ease the plight of its people.

The government may instead decide to funnel economic gains back into the military, and so pose an even greater threat to peace, he added.

US policymakers must be on guard for such an outcome -- described as "the worst of all worlds" by Brookings Institution scholar Joel Wit, at another forum here.

But if tensions do ebb and North Korea reduces its military, "you are going to have a lot of people thinking major changes are underway, and major (strategic) changes are necessary," said fellow Brookings expert Robert Suettinger.

"This is going to be very difficult not only in Korea but Japan," which could face even more domestic pressure to reduce its own US garrison, he said.

The US military still maintains 20 bases in South Korea, mostly opened during and after the 1950-53 Korean War.

Pyongyang's official media makes frequent calls for US troops to be pulled out.

A latest set of talks between the United States and North Korea ended last month in Rome, with little agreement.

North Korea has called on the United States to ease sanctions, while the United States is concerned over Pyongyang's ballistic missile program.

Under a 1994 deal, a US-led international consortium promised to complete construction of nuclear power plants by 2003 in return for Pyongyang freezing its nuclear weapons program.

The Korean talks will also be closely watched in the United States, as they have implications for a proposed missile defence shield currently being discussed here.

North Korea is among the ranks of so-called "rogue nations" cited by supporters of the scheme as possible threats to the US mainland.

Pyongyang sparked alarm here and in Japan when it tested a long-range missile in 1998.