Facebook Inc. (FB.O) Chief Operating Officer Sheryl Sandberg said “a few” advertisers have paused their spending as they wait for the company to answer questions on user privacy.

“We’ve seen a few advertisers pause with us and they’re asking the same questions that other people are asking,” Sandberg said. “They want to make sure they can use data and use it safely.”

Sandberg said she is having “reassuring conversations with advertisers, just as we are with people,” about how Facebook has built privacy into its system. The company makes almost all its revenue and profit from advertising.

The social network is reviewing its products and data policies to find further ways to protect users from being exploited, after reports that Cambridge Analytica, a political consultant, obtained information on as many as 87 million people without their permission. That crisis has led to broad questions about how Facebook treats users’ data. Chief Executive Officer Mark Zuckerberg is scheduled to testify about the issue at congressional hearings next week.