Hackers have offered to sell the login information for more than 32 million Twitter users.
A spokesperson for Twitter said: "We are confident that these usernames and credentials were not obtained by a Twitter data breach – our systems have not been breached. In fact, we've been working to help keep accounts protected by checking our data against what’s been shared from recent other password leaks."
Reports suggest that the hackers are the same ones who stole information from the Russian social media website VK last week.