“Russian operatives used Facebook to publicize 129 phony event announcements during the 2016 presidential campaign, drawing the attention of nearly 340,000 users — many of whom said they were planning to attend,” the Washington Post reports.

It’s not possible to know how often people gathered in response to the sham announcements, but the numbers highlight how Russian operatives were successful in prompting Americans to express a willingness to take action. In some cases, Russians allegedly working in an office building in St. Petersburg motivated at least some people to mobilize behind various causes, a striking accomplishment for a foreign influence operation.