California's top prosecutor said Wednesday that Facebook has failed to comply with subpoenas as part of a state probe into its privacy practices.

Attorney General Xavier Becerra called Facebook's response to the information demands "patently inadequate," noting that his office has been investigating the internet company since 2018. "We are left with little choice but to seek a court order compelling Facebook to faithfully comply with our duly authorized subpoenas," he said in a statement.

According to a filing with the San Francisco Superior Court, Becerra said Facebook took a year to fully respond to an initial subpoena in June 2018 related to the Cambridge Analytica scandal. The attorney general then asked for more information, including communications among executives related to developers' access to user data and privacy-related news stories.

Facebook "broadly refuses to answer the interrogatories or comply with the subpoena," the filing said, adding that the company has refused to search the emails of top executives Mark Zuckerberg and Sheryl Sandberg in response to the second subpoena.

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Facebook didn't immediately respond to a request for comment.

The investigation is into Facebook's practices related to privacy, disclosures and third-party access to user data. The state is looking into whether Facebook violated California law by deceiving users and misrepresenting privacy practices. Officials say the probe began in early 2018 as a response to the Cambridge Analytica scandal, but has since expanded.

The Federal Trade Commission in July fined Facebook $5 billion, a record for the consumer protection agency, over the company's breaches of user privacy in 2014 and 2015.

The court filing says Facebook hasn't given answers for 19 of the attorney general's questions and hasn't given any new documents in response to six document requests. The filing says Facebook isn't just dragging its feet, but isn't complying with subpoenas and questions.

California hadn't joined a separate probe involving attorneys general from New York and other states. The New York probe is looking into Facebook's dominance and any resulting anticompetitive conduct.