"Curfew would remain in force till further orders from tomorrow (Friday) morning onwards in Srinagar and all other major towns of the Valley. The step has been necessitated to maintain law and order in the Valley," a police officer said here.
Meanwhile, authorities have suspended internet services on mobile phones and on dongle appliances in the Valley while the Internet speed on broadband facilities has also been reduced.
"This has been done to prevent the spread of rumours by anti-social elements in the Valley," a senior state government official told IANS here.
The last time authorities suspended Internet facilities in the Valley was during the summer unrest of 2010 in which 110 people were killed in bloody clashes between security forces and unruly mobs.
Thursday's decision comes after tension thoughout the valley following the killing of four protesters attacking a Border Security Force (BSF) camp in Gool town of Ramban district in Jammu region.
Meanwhile, Jammu and Kashmir Chief Minister Omar Abdullah today condemned the killing of protestors in Ramban area and said such incidents had the potential to jeopardise the peaceful atmosphere in the state.
"It is highly unacceptable to shoot at unarmed protesters just because they were reportedly protesting manhandling of an Imam of their area" Omar said in a statement.