MGM Resorts International, which owns the Bellagio and MGM Grand in Las Vegas, said Thursday morning that it is still working to resolve issues five days after a cyberattack crippled operations.
Caesars Entertainment also admitted to being hacked.
On Sunday morning, hackers broke into MGM Resorts' casinos and hotels.
Slot and ATM machines were broken, elevators were down, and customers had to wait hours to check in. The company's website is down.
We couldn't achieve this without hundreds of amazing personnel that care about guests and our loyal customers. I appreciate your patience."
The corporation "took prompt action to protect our system and data, including shutting down certain systems."
The FBI has been in contact with the company since Sunday to investigate the attack.
Thursday, the Cybersecurity and Infrastructure Security Agency of the U.S.