Twitter was hit by a bug on Monday that caused users of the micro-blogging service to lose the followers of their accounts.
"We identified and resolved a bug that permitted a user to 'force' other users to follow them," Twitter said.
"We're now working to rollback all abuse of the bug that took place," the San Francisco-based startup said in a blog post.
Twitter's explanation came after a number of users of the fast-growing short-message service reported that the number of people listed as following their accounts had plummeted to zero.
"Follower/following numbers are currently at 0; we're aware and this too should shortly be resolved," Twitter said.
Twitter, which allows users to pepper their followers with messages of 140 characters or less, said last month that it has topped 105 million registered users and is adding 300,000 new accounts a day.