KTNV 13, a TV station in Las Vegas, reported that multiple gambling machines at hotels had gone offline and that several guests were unable to charge anything to their rooms, make reservations or use their digital room keys.

It was not clear how many people had been affected by the cybersecurity disruptions. MGM is a prominent casino and hotel company that has thousands of hotel rooms in Las Vegas, with properties that include Mandalay Bay, Aria, the Bellagio and MGM Grand Las Vegas.

Greg Moody, an associate professor of information systems and cybersecurity at the University of Nevada, Las Vegas, said on Monday that a “cybersecurity issue” typically means that an individual or a group has attacked the company’s network.

In MGM’s case, the attacker or attackers might have “found some gap in their armor” and used it to take down the company’s systems, said Dr. Moody, who has worked with the company and members of its tech team on several projects.

Such attacks are typically launched by hackers seeking a profit, he said. Attackers will usually steal a company’s data and hold it hostage until the company pays a price for its return. Attackers will also sell the stolen data in an underground online marketplace, where buyers seek data containing information that will enable identity theft, like names, numbers or addresses.