Dozens of activists, researchers, nonprofits, and journalists have been warned by Twitter that their accounts on the social media site have been targeted by nation-state hackers.

In an unprecedented move, Twitter has alerted some users that nation-state sponsored attackers may have attempted to steal their account information -- such as email address, IP address, and phone numbers. None of the small number of Twitter user accounts targeted appear to have been successfully breached, however, according to the alert.

Canadian nonprofit Coldhak said it was alerted by Twitter on Friday of the attack attempts, and its CEO told Reuters the organization hasn't experienced any effects of the attack attempts on its @coldhacka account.

The email from Twitter said, in part: "At this time, we have no evidence they obtained your account information, but we're actively investigating this matter. We wish we had more we could share, but we don't have any additional information we can provide at this time."

Coldhak is keeping a running list of Twitter users reporting that they were alerted of the attacks.

Twitter apparently is following a similar strategy and policy by Google and Facebook to warn their users of any state-sponsored hacking attempts.