It was unclear how many users received the warnings, which were issued over the weekend and were the first of their kind for Twitter.
Coldhak, a Canadian-based non-profit group, posted a copy of the warning that Twitter sent them.
"As a precaution, we are alerting you that your Twitter account is one of a small group of accounts that may have been targeted by state-sponsored actors," read the message .... http://finance.yahoo.com