The big Twitter hack

Twitter says 130 accounts were targeted in a major cyber-attack of celebrity accounts

However, Twitter says only a "small subset" of those 130 accounts had control seized by the attacker.

The security breach saw accounts including those of Barack Obama, Elon Musk, Kanye West and Bill Gates tweet a Bitcoin scam to millions of followers.

Twitter said it was still trying to work out if private data - which could include direct messages - was stolen.

"We're working with impacted account-owners and will continue to do so over the next several days," the company said, through its official support account.

"We are continuing to assess whether non-public data related to these accounts was compromised," it added.

The FBI is now investigating.

What do we know about the attackers?

Bitcoin is extremely hard to trace and the three separate crypto-currency wallets that the cyber-criminals used have already been emptied.

The digital money is likely to be split into smaller amounts and run through so-called "mixer" or "tumbler" services to make it even harder to trace back to the attackers.