Carnival Corp. says it was the victim of a ransomware attack that likely got some personal information about the cruise company’s guests and employees. First detected Saturday, the attack accessed an encrypted portion of technology systems for one of the cruise line’s brands and certain data files were downloaded.

Carnival operates Carnival Cruise Line, Princess Cruises, Holland America Line and other brands, but did not specify which cruise line was affected.

In a filing with the US Securities and Exchange Commission Carnival Corp. also didn’t say how many people’s personal information may have been accessed, and spokesman Roger Frizzell said in an email that the company wasn’t releasing any information other than what was in the securities filing.

Carnival says it has launched an investigation into the ransomware attack and notified law enforcement. The Miami-based company also said it has reinforced the security of its information systems.