Popular microblogging site Twitter said in a Friday blog post that some "unusual access patterns" had been detected on the Twitter network this week, hinting that the personal data of nearly 250,000 users had probably been accessed by hackers.

Earlier this week, Twitter had said in a previous blog post that hackers' attempts to gain access personal information of users had been detected by the site; and that it had discovered "one live attack and [was] able to shut it down in process moments later."

However, in its Friday confirmation of the hack, Twitter said that the hackers had apparently gained access to user data, including usernames, email addresses, session tokens, as well as encrypted or salted versions of passwords.

Twitter also added in the Friday blog post that it had not only rest the passwords of the users, but had also revoked session tokens for the accounts of affected users. The company also added that it will send an e-mail notification to the affected users, informing that they would have to rest their passwords, as they will not be able to log in to the Twitter network with their old passwords.

Further adding that it believed that the attack was neither the work of amateur hackers nor was it an isolated hacking incident, Twitter said that even those users who remained unaffected by the attack should use this experience to ensure that they follow "good password hygiene, on Twitter and elsewhere on the Internet."