A senior American diplomat is holding talks in Beijing with Chinese officials on America's plan to build a shield against missile attack.

China has repeatedly expressed its opposition to the United States' plan for missile defence, saying such a system could spark a new arms race.

Talking China out of its trenchant opposition to NMD is going to be tough.

James Kelly's trip to China is part of a world-wide effort by the Bush administration to allay international suspicion of the American plan for the so-called Son of Star Wars system.

His talks with senior Chinese officials are scheduled to last only a day, and before they got under way, Mr Kelly said he would try to assuage the concerns that China has expressed.

Shared goals

He said curbing the threat posed by weapons of mass destruction was a key element in maintaining peace and stability in East Asia, and that this goal was something China shared with the United Sates.

Mr Kelly is new to his job; it is his first trip to China as assistant secretary of state, and talking China out of its trenchant opposition to NMD is going to be tough.

James Kelly: The Chinese wanted a more senior negotiator

China is deeply suspicious of the planned missile defence system, and has said so many times.

China strategists believe the system would render China's own missiles ineffective, and would undermine its strategic position in Asia.

Poor relations

They say an American missile shield will spark a new arms race in Asia, and some hard-line analysts here believe that missile defence is specifically designed to counter China's military modernisation and its growing regional power.

Diplomats say the Chinese side is also offended that the Americans have not sent someone more senior to talk to them about missile defence, and Mr Kelly's task is further complicated by the fact that relations between the US and China are at a low point.

Last month's spy plane crisis and Mr Bush's commitment to sell a sizeable package of weapons to Taiwan have soured the atmosphere in which these talks are going to take place.

Gary Milholin, of US arms control think-tank, the Wisconsin Project, told the BBC: "Mr Kelly can hope at least to show that the US has not ignored China.

"He will say that missile defence is not directed at China, it is directed at rogue states such as Iran, Iraq and North Korea who may some day have missiles to hit the US."