London: Social networking site Twitter has revealed that around 250,000 user accounts have been hacked by anonymous hackers in a massive security breach.
Stating that the breach was not an amateur attack, Bob Lord, Twitter's director of information security, said that after investigation, it has been found that the hackers may have accessed limited user information like usernames, email addresses, session tokens and encrypted versions of passwords for the affected users, the Guardian reports.
Lord also said that as precautionary security measures, the company had reset passwords and revoked session tokens for these accounts.
He added that the company did not believe it was an isolated incident as the sophistication of the attackers has led them to believe that other organisations may have been similarly attacked.
Twitter had recently announced that it had detected unusual access patterns across the network and had identified unauthorised attempts to access user data that had led to accounts being compromised.
The site discovered one live attack that it was able to shut down several minutes later but not before the hackers had gained access to thousands of accounts.
The attack on Twitter is the latest in a string of high-profile security breaches on US technology and media companies.