SAN FRANCISCO - In the latest online attack, Twitter says hackers may have gained access to information on 250,000 of its more than 200 million active users.

In a blog posting Friday, Twitter says it detected attempts this week to gain access to its user data. It shut down one attack moments after it was detected.

But it discovered that the attackers may have gained access to usernames, email addresses and encrypted passwords belonging to 250,000 users. Twitter has reset the pilfered passwords and sent users email advising them that they'll have to create a new one.

Twitter noted a recent uptick in breaches at U.S. media and technology companies. The New York Times and The Wall Street Journal reported this week that their computer systems had been infiltrated by China-based hackers.