Facebook users may have to pay to disallow their data to be used for targeted advertising, the company’s Chief Operation Officer Sheryl Sandberg told NBC News on Thursday.

The social media company has been facing tremendous criticism after it came to light that it had known British firm Cambridge Analytica had been harvesting the data of Facebook users for years. Cambridge Analytica is accused of using the information of 50 million Facebook users to help the campaign of US President Donald Trump before the 2016 election.

In an interview with the “Today” show, Sandberg was asked if Facebook will come up with a tool to allow people to restrict the social network from using their profile data to stop targeted ads. Sandberg said the company already has different tools to opt out of various apps. “We do not have an opt-out at the highest level,” Sandberg said. “That would be a paid product.”

Sandberg further said Facebook does not give away its users’ information, evn though the company’s service depends on the users’ data.

Cambridge University professor Alexandr Kogan’s firm was accused of passing on data from an app it created to Cambridge Analytica, which allegedly used it to influence voters in the election campaign. She also acknowledged Facebook’s mistake for not checking whether Cambridge Analytica had deleted users’ data.

“We had legal assurances from them that they deleted. What we did not do was the next step of an audit and we are trying to do that now,” Sandberg said.