Facebook has sued a pair of Ukrainian men for developing and operating applications stylized as horoscopes and quizzes that illegally lifted users' data.

The federal lawsuit, filed Friday in the Northern District of California, alleges Gleb Sluchevsky and Andrey Gorbachov were behind web applications that tricked users into installing “malicious” web extensions that allowed the defendants to scrape data from users' social media profiles, and to place advertisements in their news feeds.

Through their work, which lasted from 2016 up until late last year, the defendants affected about 63,000 browsers visited by Facebook users, the complaint said. The company, which is seeking damages, says it took a $75,000 hit investigating and addressing the defendants' acts.

The lawsuit represents Facebook's latest legal effort to target foreigners. The social media giant recently targeted Chinese companies for selling fake Facebook and Instagram accounts. The social media giant has also faced intense public scrutiny over the handling of its users' data.

Friday's complaint said the Ukrainians' work “interfered with and undermined Facebook's relationship with its users,” adding that they “directly and proximately caused and continue to cause irreparable harm and injury” to the site.

The defendants began their operation in 2016 by using aliases to create Facebook accounts and register as web application developers, according to the lawsuit. They ran at least four applications, which were available on publicly accessible websites and targeted mostly Russian and Ukrainian speakers. The apps claimed to offer horoscopes, and character and popularity assessments, according to the complaint.

Users who logged into the apps using Facebook were told they were giving access to a limited amount of their public profile information, according to the complaint.

“In fact, Defendants knew that the applications were designed to scrape the app users' public profiles on Facebook and other social networking sites, and to prompt users to install malicious extensions for the purpose of manipulating the users' browsers and collect the users' private and non-publicly viewable lists of friends when the app user visited the Facebook site,” according to the complaint.

The lawsuit claims the developers violated the Computer Fraud and Abuse Act, and California law.

Facebook said it disabled the men's known accounts last October. The social media site said in its complaint that it publicly announced it had concluded an investigation into the extensions, contacted law enforcement, and told users how to uninstall the extensions. It said it also contacted browser makers to ensure the extensions were no longer available.

Lawyers from Tucker Ellis, including partners David Steele, Howard Kroll, and Steven Lauridsen, are representing Facebook. Tucker Ellis also represents Facebook in its suit filed against the Chinese companies last week.

One of the lawyers referred questions to Facebook's press office, which did not immediately respond to a request for comment.

Also signed onto the complaint are Jessica Romero, Michael Chmelar, and Stacy Chen, who are identified as attorneys at Facebook.