MGM Resorts International was hacked by the same group of attackers that breached Caesars Entertainment Inc. weeks earlier, according to four people familiar with the matter.

The hackers demanded a ransom from MGM, according to two of the people. It wasn’t immediately clear how much ransom was requested or if the hackers deployed ransomware to lock up the company’s files.

Caesars didn’t respond to messages seeking comment, but the company is expected to disclose the cyberattack imminently in a regulatory filing.

MGM declined to respond to questions about the attack. In a statement on Tuesday, MGM said the investigation is …