MUMBAI — In many countries, Facebook is contending with a darkening reputation as a vehicle for disinformation and false news. The most recent example: Sri Lanka.

This week, the island country sought to block access to the social network, as well as two other platforms that Facebook owns, WhatsApp and Instagram, in an attempt to stem mob violence directed at its Muslim minority. Citing inflammatory posts on Facebook and WhatsApp, the Sri Lankan government ordered internet providers and mobile phone carriers on Wednesday to temporarily block the services along with Viber, another messaging app.

“These platforms are banned because they were spreading hate speeches and amplifying them,” Harindra B. Dassanayake, a government spokesman, said in a phone interview on Thursday. Sri Lanka’s government has also imposed a nationwide state of emergency after violence broke out Sunday in one of the island’s central cities, where dozens of Muslim businesses, houses and at least one mosque were attacked. At least one person was killed.

Sri Lanka is the latest country to grapple with hate speech being magnified on Facebook, especially in parts of the world that have only recently come online. As use of the social media platform has ballooned in recent years, so have cases of extremist fringe groups using Facebook’s reach to magnify their messages.