There may be relief in the United States that the stand-off with China has come to an end, but the island of Taiwan is still concerned that its own interests may have been harmed by the affair.

Tsai Ing-Wen: Developments must be watched carefully

Tsai Ing-Wen, the head of the island's Mainland Affairs Council - the government department that deals with China - said Taiwan must now observe developments carefully.

Her comments underscore the sense of unease in Taiwan that the island's interests may be harmed by the stand-off.

Tsai Ing-Wen indicated there were still several delicate issues for Washington and Beijing to resolve, including the return of the aircraft, and the future of US reconnaissance flights in the area.

Arms sales

Taiwan's biggest concern is Washington's imminent decision on its annual arms sale to the island.

The fear is that Taiwan will not get the weapons it is seeking, either because China uses the spy plane incident to put direct pressure on the United States, or because Washington now takes a more cautious line towards Beijing.

The most sensitive component of the forthcoming arms deal are destroyers equipped with the Aegis radar system - China particularly objects to Taiwan obtaining Aegis because it could one day be used as part of the missile defence shield Washington wants to develop.

Pressure

Before the spy plane incident, most observers believed President Bush was unlikely to agree to sell Aegis to Taiwan this year.

President Bush: Will he steer a middle way?

While some in Taiwan are concerned the sale is now even more sensitive, others believe Beijing's behaviour over the spy plane incident may increase the pressure from parts of Congress and the American military for Taiwan to be given Aegis.

A middle road would be for President Bush to say the destroyers would be built, but only eventually sold to Taiwan if China continues to add to its arsenal of missiles and other weapons targeting the island.

And Taiwan's China Times newspaper has also suggested Taiwan might benefit from the stand-off, because it could force Washington and Beijing to open new channels of communication.