SINGAPORE, April 6 (Reuters) - Chinese state-owned telecom firms are developing a $500 million undersea fiber-optic internet cable network that would link Asia, the Middle East and Europe to rival a similar U. China's three main carriers – China Telecommunications Corporation (China Telecom), China Mobile Limited and China United Network Communications Group Co Ltd(China Unicom) – are mapping out one of the world’s most advanced and far-reaching subsea cable networks, according to the four people, who have direct knowledge of the plan. Hmaidi said if data has to follow routes that are approved in Washington and Beijing, then it will become easier for the United States and China to manipulate and spy on that data; internet users will suffer a degradation of service; and it will become more difficult to interact or do business with people around the world