They did the same thing in 2017 during the anti-corruption protests in Turkey. This is just a means to prevent atrocities on behalf of Erdogan's government and the military from leaking out into the public sphere.

EDIT: 2014 also: https://www.bbc.com/news/world-europe-26677134

> This comes after PM Recep Tayyip Erdogan vowed to "wipe out Twitter" following damaging allegations of corruption in his inner circle.