Facebook has extended its fact-checking function to Hong Kong in an effort to curb false news.

The social media platform announced yesterday it is partnering with Agence France-Presse, the international news agency, in rating the accuracy of stories - including photos and videos - on Facebook and show untrue stories lower on its News Feed to "significantly reduce their distribution."

Content in English and Chinese will be fact-checked following a standard set of criteria.

"We identify news that may be false using signs such as feedback from people on Facebook. Fact-checkers may also identify stories to review on their own," it said.

AFP will classify content into nine rating options, including false, false headline, mixture, true, opinion or prank.

Content deemed to be false, have a false headline, or a mixture of accurate and inaccurate information will be demoted on News Feed.

The fact-checker may also identify content as satire when it is easily understood to be ironic or humorous.

"Pages and websites that repeatedly share false news will have some restrictions, including having their distribution reduced," Facebook said. "They may also have their ability to monetize and advertise removed, and their ability to register as a news page removed."

The move comes after Twitter and Facebook said last month they had dismantled a state-backed social media campaign originating in the mainland that sought to undermine protests in Hong Kong.

It also comes as 19 international internet associations demanded the SAR ensure the stability and openness of the internet after reports suggested Chief Executive Carrie Lam Cheng Yuet-ngor may invoke the Emergency Regulations Ordinance and limit telecommunications via the internet, including Telegram and online forum Lihkg.

"On behalf of more than 200 organizations from over 70 countries we implore you to keep the internet open and secure in Hong Kong, drop any consideration of using emergency powers to block internet communication, and ensure that messaging services are not disrupted by government orders or by cyber attacks," the groups wrote in an open letter.

"We estimate an internet shutdown could conservatively cost Hong Kong US$425 million [HK$3.31 billion] per day in direct economic impact, and will slow the realization of economic, social and cultural rights broadly," they wrote.