"We know hartal would not affect government policy towards us but it is the only option to express our collective grief," separatist leaders Mirwaiz Umar Farooq, Syed Ali Shah Geelani and Mohammad Yasin Malik said in a joint statement.
They asked the people to observe complete shut down tomorrow and day after against the death of six civilians.
The separatists hit out at the PDP saying that the ruling party had become "morally bankrupt".
Violence marred the Srinagar Lok Sabha bye-elections today as six people were killed and several injured in firing by security forces on rampaging mobs in various parts of the constituency.