A scholar from a central government think-tank said Ms Wu's extensive itinerary and the purchases made in different states were aimed at appeasing state governments and congressmen from various parts of the country.

Niu Jun, an international relations expert at Peking University, said Beijing was well aware of anti-China sentiment in the US ahead of its mid-term elections and would have to face up to bilateral trade tensions.

'The trade dispute is something that cannot be evaded. So why not take the opportunity of the trip to do something?' he said.

A US source said most of the purchases would be completed during Ms Wu's trip and Mr Hu would focus on policy pronouncements during his four-day visit.

Mr Hu, who has insisted on a reception equal to that given to his predecessor, Jiang Zemin, on his first visit to the US in 1997, will be eager to prove his diplomatic and public relations skills to his hosts and the audience back home during his first official visit to the US as China's president.

His audiences will obviously be carefully chosen. On this trip, the president will dine at the lakeside residence of Microsoft chairman Bill Gates near Seattle, together with other industry leaders from the software and information technology sectors.

While China's commitment to intellectual property rights will obviously be a key topic, the occasion will also be a public relations test for Mr Hu, whose carefully scripted speeches are usually rigid and offer few surprises.

In contrast to the comparatively colourful Mr Jiang, who would sing and deliver English speeches on overseas tours, Mr Hu is better known for his caution and meticulousness, and personally vets the scripts of his speeches.

Sources say China Central Television has even stopped live broadcasts of Mr Hu's overseas trips in recent years in order to better control the message that goes out. In a rare although not unprecedented move for a Chinese leader, dozens of top China experts from American think-tanks - many of them from the east coast - will fly to Seattle to meet Mr Hu on Wednesday at the invitation of Zheng Bijian, chief of the mainland's China Reform Forum think-tank. Ironically, the meeting will take place a day before the president flies east himself.

Wu Xinbo , from Fudan University's Centre for American Studies, said the so-called think-tank diplomacy started in the past decade when Beijing realised the influence US think-tanks and lobbyists had in Washington.

The address to political and business leaders in Washington next Thursday will be a crucial test of Mr Hu's ability to engage and persuade an American audience.

'He will have to give figures and say something concrete rather than stating general principles,' Dr Niu said.

A former Taiwanese deputy defence minister and president of the Foundation on International and Cross-Strait Studies, Chong-pin Lin, said he believed Mr Hu would reveal a more relaxed attitude to religious freedom at some point during his visit. 'The one possible gift is a reconsideration or shift on Beijing's religious policy,' he said.

Dr Lin said the recent remark by State Administration for Religious Affairs director Ye Xiaowen that the Dalai Lama might be invited to visit China if he abandoned the pursuit of Tibetan independence, and the recent exchanges with the Vatican indicated Beijing might soften its religious policies.

US President George W. Bush has said Taiwan will be one of three main topics on the agenda for his talks with Mr Hu, together with the bilateral trade imbalance and religious freedom.

Dr Lin said contacts between the Chinese and US governments had never been closer since 1949 and, while he expected some sharp words would be exchanged, both sides would get back to working out solutions eventually.

'Beijing and Washington will not refrain from voicing their differences, but they do that as a ritual,' he said. 'As soon as they state their differences they go on to the real issues ... to solve problems.'