Facebook Inc. said early Thursday that it had removed pages and accounts linked to what it said were two Russia-based misinformation campaigns, the latest step in the social-media company’s effort to prevent misuse of its service.

The company removed about 500 pages and accounts on both Facebook and its Instagram photo service, Facebook cybersecurity policy head Nathaniel Gleicher said in a statement.

Facebook said it traced both campaigns to Russia. One of them operated in Ukraine, with the people behind the accounts representing themselves as Ukrainian and sharing local news stories. Facebook said that campaign shared technical overlap with Russia-based activity before the 2018 U.S. midterm elections, including behavior that shared characteristics with a Kremlin-aligned organization called the Internet Research Agency.

The other campaign operated in Central Asia, as well as Central and Eastern Europe. Posts represented as coming from independent news or general-interest pages were about topics including anti-NATO sentiment. Facebook said the pages and accounts in this campaign were linked to employees of Sputnik, a Moscow-based news agency.

A Sputnik representative said the company’s journalists focus on only news, and that Facebook’s decision to block some of its pages is tantamount to political censorship. Russian authorities weren’t immediately available to comment.