The European medicines regulator said on Tuesday some COVID-19-related documents and data that were accessed in a cyber attack it had disclosed in early December have been leaked on the internet.

The European Medicines Agency (EMA) did not provide details on which documents or data were made available online, but said necessary action was being taken by law enforcement authorities.

Hacking attempts against healthcare and medical organizations have intensified during the COVID-19 pandemic as attackers ranging from state-backed spies to cyber criminals hunt for valuable information.

“The Agency continues to fully support the criminal investigation into the data breach and to notify any additional entities and individuals whose documents and personal data may have been subject to unauthorized access,” the EMA said.

The watchdog has not so far named the third parties who were affected, but Pfizer and BioNTech announced soon after the EMA’s initial disclosure that documents relating to their vaccine were accessed in the incident.