Persuading China that missile defence is a benign system in this climate will be very difficult indeed

Now it is China's turn.

The delegation, led by James Kelly, the new assistant secretary of state for Asia and the Pacific, is expected to arrive in Beijing between 0900 and 1100 GMT.

It will try to reassure the Chinese that the missile shield is not aimed at them.

China remains implacably opposed to the American plan, but a spokesman also said that China was willing to hold consultations on the issue - an indication that the door isn't completely closed.

China fears that its own small nuclear and missile capacity will be rendered useless by an American missile shield.

US wants protection from "rogue states"

It fears also that such a shield might include American allies in Asia, especially Taiwan, which China claims as its own territory.

Chinese analysts say that if the missile shield is built China will certainly upgrade and expand its own missile capacity.

They say that would mean a new arms race in Asia.

Strained ties

The American delegation arrives in Beijing at a difficult time.

A crippled American spy plane still sits on the tarmac in south China and China hasn't said when it can leave.

The United States has sold more weapons to Taiwan and several American-based academics have been arrested inside China; some of them have been charged with espionage.

All these things are contributing to a highly charged and irritable atmosphere.

Persuading China that missile defence is a benign system in this climate will be very difficult indeed.