Turkey has banned several social networks, including Twitter, from advertising after they failed to establish a representative in the country under law.
The ban follows the passing of a new law in Turkey in October, which forced social networks to remove content at the request of the authorities and maintain a legal presence in the country.
Twitter's live video-sharing application Periscope and the social network Pinterest have also been banned from advertising revenue, according to a decision published in the Turkish Official Gazette.
Critics of the law say the legislation amounts to censorship of online content after the government had previously tightened its grip on mainstream media following a coup attempt in 2016.
But Turkey's Deputy Minister of Transport and Infrastructure, Omer Fatih Sayan, defended the law on Twitter, saying it was aimed at fighting "digital fascism".
"We are committed to doing whatever it takes to protect your data, privacy, and rights," Sayan tweeted, adding "harassment, abuse, slander and rights violations are not a freedom but a crime".
The deputy minister also expressed hope that Twitter and Pinterest would obey the regulations, otherwise risking a reduction in bandwidth in Turkey.
Turkish authorities have planned to halve the bandwidth of companies that contradict the law by April and then further reduce it by 90 per cent in May, making them effectively inaccessible.
"We do not want any of our citizens to be deprived of the services provided in our country," said Sayan.
Before the ban on advertising revenue came into force, Facebook stated that it would appoint a representative in Turkey but reaffirmed its commitment to freedom of expression. Other platforms including YouTube and TikTok have abided by the legislation.
Amnesty International has warned the social media companies risk "becoming instruments of state censorship" in Turkey.
"We are calling on social media companies not to contribute to Turkey's censorship of online content and not to expose users to the risk of arbitrary arrest and prosecution by handing over their private data to Turkish authorities," added Sarah Clarke, Article 19’s Head of Europe and Central Asia Programme.
Turkey has so far fined social media platforms 40 million Turkish liras (€4.4 million) for non-compliance with the law.
The country's government passed the legislation in July, less than one month after President Recep Tayyip Erdoğan called for a "cleaning up" of social networks.