Alphabet's Google said on Friday (Aug 14) it would no longer provide data in response to requests from Hong Kong authorities.
It comes after the enforcement of the new national security law imposed by China.
The U.S. tech giant said it had not produced any data since the sweeping new legislation took force in June.
A Google statement read: "As always, authorities outside the U.S. may seek data needed for criminal investigations through diplomatic procedures,"
It said it reviewed all requests for user data and pushed back on "overly broad ones" to protect the privacy of users.
The Washington Post newspaper reported earlier on Friday that Google would stop responding directly to data requests from Hong Kong authorities.
That implies the company would now treat Hong Kong effectively the same as mainland China in such dealings.
The national security law has drawn criticism from the U.S. administration.
And Washington decided to end the former British colony's special status under U.S. law.
In July, Facebook, Google and Twitter suspended processing government requests for user data in Hong Kong.
Tech companies have long operated freely in Hong Kong, a global financial hub.
Internet access has traditionally been unaffected by the firewall imposed in mainland China, which blocks the American tech firms.