<p>'Grave concern' Turkish author and Nobel prize-winner Orhan Pamuk is among the authors calling on Turkey to end social media censorship. Photograph: Murad Sezer/Reuters</p><p>Turkey's Nobel laureate Orhan Pamuk has said that the situation in his country "is going from bad to worse and even towards terrible" following the government's attempts to block access to Twitter, as a phalanx of major writers, from Zadie Smith to Guenter Grass, line up to state their "grave concern" about "the freedom of words" in Turkey today.</p><p>The authors, who also include Salman Rushdie, Margaret Atwood, Karl Ove Knausgaard, and Grass and Pamuk's fellow Nobel laureate Elfriede Jelinek, have added their names to a joint letter from PEN International and English PEN which calls last week's ban on Twitter "an unacceptable violation of the right to freedom of speech". The Turkish government restricted access to the micro-blogging website, and prime minister Recep Tayyip Erdogan indicated the ban could be extended further, saying he would not "leave this nation at the mercy of YouTube and Facebook" and pledging to "take the necessary steps in the strongest way".</p><p>On Thursday, he appeared to follow up that threat as Turkish media reported that the country's telecommunications authority (TB) had blocked YouTube as a "precautionary administrative measure". The latest curbs came hours after an audio recording of a high-level security meeting was leaked on the video-sharing website. Turkey previously banned YouTube in 2007, but lifted the ban three years later.</p><p><a href="http://www.theguardian.com/books/2014/mar/28/zadie-smith-rushdie-pamuk-pen-international-letter-turkey-twitter-ban">Keep reading...</a></p><p>Read also:</p><p><a href="http://www.motherjones.com/politics/2014/03/turkey-facebook-youtube-twitter-blocked">MAP: Here Are the Countries That Block Facebook, Twitter, and YouTube</a> (Mother Jones)</p><p><a href="http://www.cnn.com/2014/03/27/world/europe/turkey-youtube-blocked/">Turkey blocks YouTube days after Twitter crackdown</a> (CNN)</p><p><a href="http://mashable.com/2014/03/28/quotes-turkey-erdogan-social-media/">&#039;Twitter, Mtwitter!&#039;: Turkish Prime Minister&#039;s 9 Craziest Quotes About Social ...</a> (Mashable)</p><p>Explore: <a href="http://news.google.com/news/more?ncl=djIA1nTYFtIw7FMIfNzXhx7ZCYqcM&authuser=0&ned=us">1,021 additional articles.</a></p>