The ban will be in place for a month or till further orders, whichever is earlier, said an order issued by Principal Secretary Home R K Goyal.
"In the interest of maintenance of public order, the government hereby directs all internet service providers that any message or class of messages to or from a person or a class of persons relating to any subject or any pictorial content through the following social networking sites shall not be transmitted in Kashmir valley with immediate effect for a period of one month or till further orders, whichever is earlier," he said in the three-page order.
The sites and applications which will be inaccessible in the valley include Facebook, Twitter, Whatsapp, Wechat, QQ, Qzone, Google Plus, Skype, Line, Pinterest, Snapchat, Youtube, Vine and Flickr.
An earlier report said the government had suspended internet services in Kashmir for a month but this was not correct.
To the ban the social networking sites and Apps, Goyal invoked the powers conferred on Government under Indian Telegraph Act 1885 read with Indian Telegraph (Amendment) Rules 2007 to ban these sites and applications.
"On careful examination of all relevant factors, it is observed that the use of social media platforms, which are being misused by anti-national and anti-social elements by transmitting inflammatory messages in various forms are immediately required to be regulated/curbed," the order reads.
It said, "The anti-national and inimical elements largely succeed in transmitting unverified, objectionable and inflammatory material and content through the medium of these social networking sites."
It was being "felt that continued misuse of social networking sites and instant messaging services is likely to be detrimental to the interests of peace and tranquility in the state," the order said.
"It was also observed during law and order disturbances of 2016 in the Kashmir valley that anti-national and subversive elements extensively misused social media sites and instant messaging services for vitiating peace and instigating violence, which caused large scale damage to life and property," it added.
The move comes against the backdrop of repeated student protests in Kashmir, which the authorities believe are fanned through social media.
Some days back, a police official had said that 350 WhatsApp groups were being used to spread rumours in Kashmir and the government had cracked down, shutting 90 per cent of these groups.
The mobile internet services were suspended in Kashmir on April 17, following widespread student protests in the valley against alleged highhandedness of security forces.
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