Former chief executive Tung Chee-hwa is playing an increasingly visible role in boosting Sino-US ties as he gave speeches on the matter at the United States Military Academy at West Point and The Economic Club of New York on Tuesday. Tung, who was appointed vice-chairman of the Chinese People's Political Consultative Conference after stepping down as chief executive in 2005, has been chairman of the China-United States Exchange Foundation since its establishment in Hong Kong in 2008. According to Tung's public relations agent, the military academy invited him to speak about the mainland's economic and political developments and its foreign policy. In his speech, Tung stressed that exchanges between the Chinese and Americans were key to building mutual trust, and he encouraged cadets of the renowned military institution to visit the mainland. On the same day, Tung gave another speech at The Economic Club of New York at a dinner reception at its invitation. Hong Kong's former leader said Sino-US ties were currently the most important bilateral relationship in the world. The relationship had overcome tremendous challenges and that people from both countries had gained from the co-operation, he said. But both nations must deepen their collaboration, Tung said, calling the next 10 years an 'irresistible window of opportunity'. However, the high US jobless rate was due not to China's lower-cost exports, but rather due to the 2008 global financial crisis, he said. In the past decade, US exports to China had surged and they would continue to rise, creating more jobs in the US, Tung added. He also urged an increase in bilateral trade in areas such as commodities and sustainable energy. A former shipping executive from a wealthy family in the industry, Tung has been taking on the role of an unofficial bridge between China and the United States since 2008, thanks to the use of his extensive business and diplomatic network. In February, he attended some meetings alongside Vice-President Xi Jinping during Xi's visit to the United States. And Tung was visible during US President Barack Obama's first visit to Beijing in November 2009. He also hosted top US officials when they visited Hong Kong.