Officials from the United States are echoing the exhortation of the 19th-Century forebears and telling their countrymen to "Go west" -- but this time in China.

More American entrepreneurs and companies were eyeing China's less developed western hinterland, said William A. Brekke, commercial counselor of the U.S. embassy in China.

"Western China's provinces are quite like the American western regions years ago, full of business opportunities. Both American and Chinese companies can find chances for cooperation here," Brekke said at the sixth China Western Region International Economic Cooperation Fair in Xi'an, northwest China's Shaanxi province.

The fair is held in conjunction with the 11th Investment and Trade Forum for Cooperation between East and West China, which over the past 10 years, has seen the signing of 1,305 foreign investment contracts worth a total 15.6 billion U.S. dollars.

More than 4,000 foreign investors from 30 countries attended this year's event.

The U.S. embassy's foreign commercial service brought representatives from the states of Kentucky, Illinois, North Carolina, Maryland and Idaho this year, making it the biggest-ever U.S. delegation to the forum.

"About 50 percent of the American companies in China are currently based in Shanghai and Beijing. What they will do next is to help American firms enter China's medium-sized cities and western regions," Brekke said.

The development of western China had strong support from China's government and big western cities, especially Xi'an and Chengdu, which were very strong in high technology, electronics and energy, said William Chu, director of Asia Pacific office of North Carolina.

He said he would recommend the western provinces to the U.S. firms wanting to do business in China.

Last month, Idaho-based Micron Technology Inc. invested 250 million U.S. dollars in a manufacturing facility in the Xi'an Hi-tech Industries Development Zone.

It was Micron's first manufacturing facility in China and is a project involving the biggest investment ever made at the Xi'an High-Tech Zone.

Applied Materials Inc., a major nanotechnology manufacturer, also opened a new technology support center here last month.

The latest in the wave of American companies "going west" is software giant Oracle, which is to open its fifth Chinese branch in Xi'an.