TWITTER CEO JACK DORSEY HAS said the company feels “terrible” after a large-scale hack targeted employees with access to the firm’s internal systems and posted a Bitcoin scam to the accounts of high-profile figures in the US.

Former US president Barack Obama, rapper Kanye West and current presidential candidate Joe Biden were among those hit by the breach, with identical messages promoting the cryptocurrency scam posted to their profiles.

Twitter has now confirmed the incident was a “co-ordinated social engineering attack” by hackers who had targeted Twitter employees with “access to internal systems and tools”.

Tweeting in the early hours of the morning, Dorsey said it was a “tough day for us at Twitter”. 

“We all feel terrible this happened,” he added. “We’re diagnosing and will share everything we can when we have a more complete understanding of exactly what happened.”

Twitter took the step of stopping verified accounts from tweeting as it dealt with the issue. 

Twitter Support tweeted that:

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.

Twitter said that the decision to stop some accounts from tweeting was “disruptive” but “was an important step to reduce risk”. 

“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.” 

With reporting from Press Association