Sony has reset the passwords of multiple PlayStation Network accounts for the third time in as many weeks.
PlayStation's US arm told affected users that the precautionary measure was taken after it detected "irregular activity" on the network.
The company told Joystiq: "We routinely monitor for irregular activity, and if such activity is detected, we may sometimes reset passwords of affected SEN accounts to protect consumers and their account information.
"The password resets are not related to an attack on, nor a vulnerability in, our data servers; it is an example of an increasingly common threat of malicious online activity."
PS4 released in North America on November 15, 2013 and two weeks later in Europe and Latin America. Worldwide PS4 sales have exceed 2.1 million units and PSN has at times struggled to cope with a large influx of new users.