Stricter controls on supercomputer exports from the United States to China are needed to curb the development of Beijing's military technology, according to testimony given last summer to the US Government by a leading trade expert. In a report titled The Export of Supercomputers to China: Implications for Peace and Security , delivered to the US Senate last year, Stephen Bryen described the sales from the US of 46 or more supercomputers to Beijing as being 'a risk to American national security' and a threat to the country's regional allies, such as Indonesia, Japan, Malaysia, the Philippines, Singapore, South Korea, Taiwan and Thailand. His testimony was given in June, during a time when the US Government was investigating cases of supercomputer sales to the mainland. Four months later, a bill preventing the free export of high-end computer systems was passed by the House of Representatives. Mr Bryen has held senior positions in the US Government overseeing technology and trade security issues. He helped negotiate and implement the 1986 US-Japan Supercomputer Agreement, which established a system to monitor and regulate sales of supercomputers. Mr Bryen called for stricter controls on exports of supercomputers to the mainland which was 'seeking to enhance its nuclear weapons and their delivery systems'. 'Supercomputers are important for China to achieve these goals. Having them will enable China to speed up the design and development process by many years, to develop advanced weapons covertly and to build far more accurate nuclear systems. 'Giving China supercomputers also enhances her ability to use advanced information warfare techniques, such as attacking our own computer infrastructure.' He described the mainland's computer networks as being 'state of the art' and 'supplied primarily by the United States'. 'Consider the supercomputer system sold to the Chinese Academy of Sciences. 'I understand this is a Silicon Graphics Challenge XL supercomputer system made up of some 32 processors. 'According to public data, this single system is faster than two-thirds of the classified systems available to the Defence Department . . . The Academy of Sciences in China is deeply involved in nuclear programmes.' Mr Bryen said there was evidence 'US companies selling supercomputers understand they will be used for military and nuclear purposes'. He cited the case of an unnamed US company that marketed supercomputers and was involved in a joint venture with a state-owned aerospace enterprise. '[It] focuses on selling high-end computers to the aerospace industry in China, much of which is involved in military work,' Mr Bryen said. 'Another distributor of supercomputers in China - Geotech - says that its target market for supercomputers includes oil and gas industries, research institutes and defence.'