Facebook Inc. said if it ever returns to China, the company will do it in a way that preserves rights to free expression and privacy -- issues that make such a move almost impossible today.

The social-media giant made the comments in a written response to questions from U.S. senators. Facebook’s stance is more cautious than Google, which is trying to get its search engine back into China. That project has sparked harsh criticism and debate from employees and outsiders, who say the company is violating its mission. Google’s leader, Sundar Pichai, has said the Chinese market is too big to ignore.

It has salespeople based there to sell ads to local companies that want to reach people outside of China. The company has also at times tried to open an office in Beijing, and once launched a photo-sharing app in the country called Colorful Balloons.

The company answered the questions as a follow-up to Chief Operating Officer Sheryl Sandberg’s congressional testimony in September.