Facebook Inc. expressed a “willingness to engage” with European Union regulators in the wake of fresh evidence showing that data on most of the social network’s 2 billion users could have been accessed improperly.

Justice Commissioner Vera Jourova is in touch with Facebook “to arrange for high-level contacts in the coming days,” her spokesman Christian Wigand told reporters at a briefing in Brussels Thursday. Wigand said the Menlo Park, California-based company contacted the EU in response to a letter from Jourova last month.

Facebook on Wednesday said data on as many as 87 million people, most of them in the U.S., may have been improperly shared with research firm Cambridge Analytica. This is Facebook’s first official confirmation of the possible scope of the data leak, which was previously estimated at roughly 50 million. It has resulted in calls from legislators and policymakers for greater regulation of social media, helping to shave billions of dollars from the company’s market value.

“The growing scale of Cambridge Analytica, Facebook case is very worrying, 87mln people were affected, also from EU,” Jourova said in a tweet Thursday. “Facebook needs to step up the response and protect the European data.”

Facebook didn’t immediately respond to emails seeking comment on the EU statements.

Zuckerberg Conference Call

Chief Executive Officer Mark Zuckerberg has apologized and promised to investigate whether Cambridge Analytica still holds the information it obtained from a third-party app creator and to broaden the probe to other developers who harvest data. On a conference call with reporters on Wednesday, Zuckerberg said his company “didn’t focus enough on preventing abuse and thinking through how people could use these tools to do harm as well.”

The shares rallied after Zuckerberg stoked optimism that the drumbeat of bad news may be coming to an end.

The company has been under pressure from lawmakers on both sides of the Atlantic as regulators have opened probes into what EU watchdogs called a “very serious allegation with far-reaching consequences.” The U.K.’s Information Commissioner’s Office, which is leading the probe in Europe, is combing through the evidence it collected during a search of the offices of Cambridge Analytica on March 23.

Facebook has updated its data policy to better spell out what information it collects and how the company uses it across the social network and other services like Instagram and Messenger. The company this week clarified that it scans chats sent via its Messenger service to make sure they abide by the overall terms, for example.

The policy changes come ahead of strict EU privacy rules that will kick in starting May 25 and apply to any company using or processing data on European citizens. Zuckerberg on the conference call on Wednesday said the changes under the so-called General Data Protection Regulation “are very positive.”

Facebook plans “to make all the same controls and settings available everywhere, not just in Europe,” albeit probably not in exactly the same format everywhere, Zuckerberg said. “We need to figure out what makes sense in different markets with the different laws and different places. But — let me repeat this — we’ll make all controls and settings the same everywhere, not just in Europe.”

Jourova on Thursday said she will seek updates on ongoing probes by EU and U.K. privacy watchdogs, as well as the U.S. Federal Trade Commission.

“The latest figures published by Facebook confirm that European users have also been affected,” Wigand told reporters in Brussels, repeating the EU’s view that “the unauthorized access to and further misuse of personal data belonging to Facebook users is not acceptable.”