In a blog from the social network’s Shabnam Shaik, a technical program manager, she said the inauthentic likes and comments appeared to come from “accounts located in Bangladesh, Indonesia, Saudi Arabia, and a number of other countries”.

She went on: “We found that most of this activity was generated not through traditional mass account creation methods, but by more sophisticated means that try to mask the fact that the accounts are part of the same coordinated operation.”

Tricks to avoid detection included redirecting traffic through ‘proxies’ to disguise their location. The company said the campaign appeared to deceptively gain new friend connections by liking and interacting with popular publisher Pages, and then send spam.

She said that as the remaining fake likes are removed, it expected 99% of impacted Pages with more than 10,000 likes will see a drop of less than 3%. “None of these likes were the result of paid ads from the affected Pages,” wrote Shaik.