Around 300 people have been arrested and an online crackdown has been launched blocking over 50 Facebook and Twitter pages, official sources say as authorities try to thwart plans by separatists and others to disrupt Prime Minister Narendra Modi's rally in Srinagar on Saturday. Among those arrested are top separatists, some of whom have called for a counter march, sources said. No parallel rally will be allowed and restrictions will be enforced in sensitive areas on Saturday, they said.