July 5 (Reuters) - An Asian industry group that includes Google (GOOGL.O), Facebook (FB.O) and Twitter (TWTR.N) has warned that tech companies could stop offering their services in Hong Kong if the Chinese territory proceeds with plans to change privacy laws. The warning came in a letter sent by the Asia Internet Coalition, of which all three companies, in addition to Apple Inc , LinkedIn and others, are members. Proposed amendments to privacy laws in Hong Kong could see individuals hit with "severe sanctions", said the June 25 letter to the territory"s privacy commissioner for personal data, Ada Chung Lai-ling, without specifying what the sanctions would be. "Introducing sanctions aimed at individuals is not aligned with global norms and trends," added the letter, whose contents were first reported by the Wall Street Journal. "The only way to avoid these sanctions for technology companies would be to refrain from investing and offering their services in Hong Kong, thereby depriving Hong Kong businesses and consumers, whilst also creating new barriers to trade." In the six-page letter, AIC managing director Jeff Paine acknowledged the proposed amendments focus on the safety and personal data privacy of individuals. "However, we wish to stress that doxxing is a matter of serious concern," he wrote.During anti-government protests in Hong Kong in 2019, doxxing - or publicly releasing private or identifying information about an individual or organisation - came under scrutiny when police were targeted after their details were released online. The details of some officers" home addresses and children"s schools were also exposed by anti-government protesters, some of who threatened them and their families online. "We ... believe that any anti-doxxing legislation, which can have the effect of curtailing free expression, must be built upon principles of necessity and proportionality," the AIC said. Facebook did not immediately respond to a Reuters request for comment, while Twitter referred questions to the AIC. Google declined to comment. The former British colony of Hong Kong returned to Chinese rule in 1997 with the guarantee of continued freedoms. Pro-democracy activists say those freedoms are being whittled away by Beijing, especially with a national security law introduced last year cracking down on dissent. China denies the charge.