Twitter announced on its official account that the hacking of several high-profile accounts is believed “to be a coordinated social engineering attack by people who successfully targeted some of our employees with access to internal systems and tools.”

“We know they used this access to take control of many highly-visible (including verified) accounts and Tweet on their behalf. We’re looking into what other malicious activity they may have conducted or information they may have accessed and will share more here as we have it,” the company added.

“Internally, we’ve taken significant steps to limit access to internal systems and tools while our investigation is ongoing. More updates to come as our investigation continues.”