Facebook is failing to rein in a “tsunami” of hate posts inflaming ethnic tensions in Assam, campaign group Avaaz has said, with content about “criminals”, “rapists”, “terrorists” and “dogs” shared almost 100,000 times.

Avaaz said the dehumanising language — often targeting Bengali Muslims — was similar to that used on Facebook about Myanmar’s Rohingya before an army crackdown and ethnic violence forced 700,000 Rohingya to flee in 2017 to Bangladesh.

A Facebook spokesperson said the company was proactively removing 65 per cent of hate speech before it was reported globally, and that its content reviewers, working in at least nine Indian languages, were rigorously trained to “catch harmful content”.

The UN warned of rising hate speech on social media in Assam as the government prepared to publish a list of Indian citizens in the state that left out nearly 2 million people.

“Facebook is being used as a megaphone for hate, pointed directly at vulnerable minorities in Assam, many of whom could be made stateless within months,” Alaphia Zoyab, a campaigner at Avaaz, said in a statement.

To be included on the register, published in August, residents had to prove their families lived in India before March 24, 1971, when hundreds of thousands of people began fleeing conflict across the border in what is now Bangladesh.

Resentment against illegal immigrants has simmered for years in Assam, one of India’s poorest states, with residents blaming outsiders, mainly Bangladeshis, for taking their jobs and land.

Avaaz, which campaigns against disinformation on social media, analysed 800 Facebook posts and comments relating to Assam and the register, and found that about 27 per cent constituted hate speech, which it estimated had been viewed 5 million times.

It flagged 213 posts to Facebook, which removed 96 of them, including one by an elected official implying that those who rape “our mothers and sisters” are “Bangladeshi Muslims”, and calls to “poison” daughters and legalise female foeticide.

Facebook has been criticised for not acting to stamp out hate speech on its platform in Myanmar and for not stopping the use of fake accounts aiming to sway public opinion in the 2016 US poll and Britain’s vote to leave the EU.

Avaaz said Facebook was too reliant on artificial intelligence hate speech detection mechanisms, and needed to put in place more human-led teams to monitor content in Assam.

“Despite the clear and present danger faced by these people, Facebook is refusing to dedicate the resources required to keep them safe,” said Zoyab. “Through its inaction, Facebook is complicit in the persecution of some of the world’s most vulnerable people.”

Facebook’s spokesperson said the use of artificial intelligence had improved its hate speech detection and that it had invested in tools to encourage people to flag up inappropriate content.