Twitter says 250,000 accounts have been hacked in a major security breach.
Anonymous hackers gained access to usernames, email addresses and passwords.
Twitter’s security team say the attack was the work of professionals.
On the Friday the social networking site noticed unusual access patterns that led to accounts being compromised.
The attack on Twitter is the latest in a number of high-profile security breaches.
The Wall Street journal and the New York Times were hit in the last 14 days.
The US newspapers both claim their systems were attacked by China-based hackers.
Twitter has 200 million users worldwide.