Facebook says it has removed more than 500 Pages and accounts that originated in Russia, some of which it claims are linked to Moscow-based news agency Sputnik.

The social network said it discovered two separate operations engaging in what it called “inauthentic behaviour” across Facebook and Instagram, involving attempts to “manipulate people”.

The accounts were removed because they had attempted to “mislead others about who they were and what they were doing”, Facebook said.

The first operation involved 289 Facebook Pages and 75 accounts representing themselves primarily as independent news or general interest pages and operating across a range of countries in central Asia and central and eastern Europe.

Facebook said it found the accounts were linked to Sputnik employees, some of which frequently posted about “anti-Nato sentiment, protest movements, and anti-corruption”.

The second operation – based on a tip-off from US law enforcement – included 107 Facebook Pages, Groups and accounts, as well as 41 Instagram accounts and focused on Ukraine.

“The individuals behind these accounts primarily represented themselves as Ukrainian, and they operated a variety of fake accounts while sharing local Ukrainian news stories on a variety of topics, such as weather, protests, Nato, and health conditions at schools,” Facebook said.

“We identified some technical overlap with Russia-based activity we saw prior to the US midterm elections, including behaviour that shared characteristics with previous Internet Research Agency (IRA) activity.”

The social network’s head of cybersecurity policy Nathaniel Gleicher said: “We’re taking down these Pages and accounts based on their behaviour, not the content they post.

“In these cases, the people behind this activity co-ordinated with one another and used fake accounts to misrepresent themselves, and that was the basis for our action.”

“While we are making progress rooting out this abuse, as we’ve said before, it’s an ongoing challenge because the people responsible are determined and well funded.

“We constantly have to improve to stay ahead. That means building better technology, hiring more people and working more closely with law enforcement, security experts and other companies. Their collaboration was critical to these investigations.”

Previous investigations in the US found Facebook had been used by Russia to post content that aimed to influence and interfere with the 2016 US presidential election.

Last year, the social network removed more than 100 accounts on the eve of the US midterm elections in November it believed were linked to “foreign entities”, having also removed more than 80 Pages, Groups and accounts in October it claimed were linked to Iran.