Zhang Dejiang (C), who chairs China's communist-controlled legislature, gestures while speaking as he takes a tour of an innovation booth at Science Park as part of an event surrounding the Belt and Road Summit being held in Hong Kong on May 18, 2016. The three-day trip to Hong Kong by Zhang Dejiang, who chairs China's communist-controlled legislature, is the first by such a senior official for four years. His visit comes as concerns grow that freedoms are under threat in semi-autonomous Hong Kong as Beijing tightens its grip. / AFP PHOTO / POOL / ISAAC LAWRENCEISAAC LAWRENCE/AFP/Getty Images

Hong Kong Chief Executive Leung Chun-ying (L) speaks while Nicholas Wang (R), Secretary for Innovation and Technology listens on at a presentation on innovation attended by Zhang Dejiang, who chairs China's communist-controlled legislature, at Science Park as part of an event surrounding the Belt and Road Summit being held in Hong Kong on May 18, 2016. The three-day trip to Hong Kong by Zhang Dejiang, who chairs China's communist-controlled legislature, is the first by such a senior official for four years. His visit comes as concerns grow that freedoms are under threat in semi-autonomous Hong Kong as Beijing tightens its grip. / AFP PHOTO / POOL / ISAAC LAWRENCEISAAC LAWRENCE/AFP/Getty Images

Zhang Dejiang (C), who chairs China's communist-controlled legislature, gestures while Hong Kong Chief Executive Leung Chun-ying (centre R) looks on as they take a tour of an innovation booth at Science Park as part of an event surrounding the Belt and Road Summit being held in Hong Kong on May 18, 2016. The three-day trip to Hong Kong by Zhang Dejiang, who chairs China's communist-controlled legislature, is the first by such a senior official for four years. His visit comes as concerns grow that freedoms are under threat in semi-autonomous Hong Kong as Beijing tightens its grip. / AFP PHOTO / POOL / ISAAC LAWRENCEISAAC LAWRENCE/AFP/Getty Images

Zhang Dejiang (C), who chairs China's communist-controlled legislature, and Hong Kong Chief Executive Leung Chun-ying (R), take a tour of an innovation booth at Science Park as part of an event surrounding the Belt and Road Summit being held in Hong Kong on May 18, 2016. The three-day trip to Hong Kong by Zhang Dejiang, who chairs China's communist-controlled legislature, is the first by such a senior official for four years. His visit comes as concerns grow that freedoms are under threat in semi-autonomous Hong Kong as Beijing tightens its grip. / AFP PHOTO / POOL / ISAAC LAWRENCEISAAC LAWRENCE/AFP/Getty Images

Zhang Dejiang, who chairs China's communist-controlled legislature, attends a presentation on innovation at Science Park as part of an event surrounding the Belt and Road Summit being held in Hong Kong on May 18, 2016. The three-day trip to Hong Kong by Zhang Dejiang, who chairs China's communist-controlled legislature, is the first by such a senior official for four years. His visit comes as concerns grow that freedoms are under threat in semi-autonomous Hong Kong as Beijing tightens its grip. / AFP PHOTO / POOL / ISAAC LAWRENCEISAAC LAWRENCE/AFP/Getty Images

Austrian President Heinz Fischer (R) looks on as Jörg Leichtfried, new minister for transport, innovation and technology of the Austrian cabinet, signs his certificate of appointment at the Hofburg in Vienna, Austria, on May 18, 2016. / AFP PHOTO / APA / HELMUT FOHRINGER / Austria OUTHELMUT FOHRINGER/AFP/Getty Images

A handout photo taken and received on May 18, 2016, shows the launch of an experimental rocket on trial which reached an altitude of 278 kilometres and a target speed of Mach 7.5 in the latest successful test of hypersonic technology in the Australian desert. A joint US-Australian military research team is running a series of 10 trials at the world's largest land testing range, Woomera in South Australia, developing the scramjet, a supersonic combustion engine that uses oxygen from the atmosphere for fuel, making it lighter and faster than fuel-carrying rockets. / AFP PHOTO / ADF / CPL Bill Solomou / ----EDITORS NOTE ----RESTRICTED TO EDITORIAL USE MANDATORY CREDIT " AFP PHOTO / AUSTRALIAN DEFENCE" NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTSCPL BILL SOLOMOU/AFP/Getty Images

A handout photo taken and received on May 18, 2016, shows the launch of an experimental rocket on trial which reached an altitude of 278 kilometres and a target speed of Mach 7.5 in the latest successful test of hypersonic technology in the Australian desert. A joint US-Australian military research team is running a series of 10 trials at the world's largest land testing range, Woomera in South Australia, developing the scramjet, a supersonic combustion engine that uses oxygen from the atmosphere for fuel, making it lighter and faster than fuel-carrying rockets. / AFP PHOTO / ADF / CPL Bill Solomou / ----EDITORS NOTE ----RESTRICTED TO EDITORIAL USE MANDATORY CREDIT " AFP PHOTO / AUSTRALIAN DEFENCE" NO MARKETING NO ADVERTISING CAMPAIGNS - DISTRIBUTED AS A SERVICE TO CLIENTSCPL BILL SOLOMOU/AFP/Getty Images