Turkey's infotech regulator on Friday blocked access to Instagram without an explanation or stating how long the ban would remain in place.
The decision led many users in Turkey to complain on X, formerly Twitter, that their Insta feed was not refreshing.
Why has Turkey blocked Instagram?
The BTK communications authority wrote on its website that "Instagram.com has been blocked by a decision on the date of 02/08/2024" without giving further details.
The move, however, followed accusations by the Ankara government that the social media platform was blocking posts related to the killing of Ismail Haniyeh, the political head of the Palestinian militant group Hamas.
The social media giant was "impeding people from publishing messages of condolence for the martyr Haniyeh," the Turkish presidency's communications spokesman, Fahrettin Altun, wrote on X on Wednesday, adding, "This is censorship, pure and simple."
Altun said Instagram had not cited any policy violations for its action.
Instagram's parent company, Meta, has yet to comment on the ban or Altun's comments.
Israel blamed for Haniyeh's killing
Haniyeh and a bodyguard were killed in a pre-dawn attack in Tehran on Wednesday, which has been blamed on Israel.
Haniyeh was a close ally of Turkish President Recep Tayyip Erdogan, and the pair last met in Istanbul in April.
On Friday, Turkey was holding a day of mourning for the Hamas political chief as concerns rose that his killing would set back the prospect of a cease-fire agreement in the nearly 10-month-old war in Gaza between Israel and the Iran-backed Hamas.
Hamas is labeled as a terrorist organization by the United States, Germany and Israel, but not Turkey.
Erdogan has described the group as "liberation fighters" as part of his criticism of Israel's military operations in Gaza.
Growing fears of regional conflict
Both Iran and Hamas have vowed revenge for Haniyeh's killing, sparking fears that the Gaza conflict may further expand into the region.
Hamas called for a "day of furious rage" on Friday to coincide with Haniyeh's burial in Qatar.
This is not the first time that Turkey has cut access to social media sites.
Wikipedia was blocked between April 2017 and January 2020 over two articles that alleged a link between the Turkish presidency and extremism.
In April, Facebook owner Meta suspended its Threads social network in Turkey after authorities stopped it from sharing information with Instagram.
Instagram has more than 50 million users in Turkey, out of a population of 85 million, local media reported.