Authorities imposed restrictions in parts of Srinagar on Monday to maintain law and order in the wake of the killing of 20 people in three separate gunfights on Sunday, police said.Joint Resistance Leadership (JRL), a separatist conglomerate headed by Syed Ali Geelani, Mirwaiz Umer Farooq and Muhammad Yasin Malik, has also called for a protest shutdown.On Sunday, 20 people -- 13 militants, four civilians, three soldiers -- were killed in the three gunfights that took place in Shopian and Anantnag districts.Over 60 civilians were injured in clashes with the security forces as protesters resorted to stone pelting near the gunfight sites.Authorities have placed Geelani, Mirwaiz and Malik under house arrest in Srinagar to prevent their participation in the protest.Heavy contingents of police and the Central Reserve Police Force (CRPF) have been deployed in the restricted areas in Srinagar.Markets, public transport and other businesses remained shut in the valley.All educational institutions were closed on Monday while exams scheduled for the day have been postponed.Train services between north Kashmir's Baramulla town and Bannihal town have been suspended.Mobile internet services have remained suspended since Sunday in south Kashmir areas while the speed of fixed line broadband connections has also been brought down to prevent uploading of provocative posts and pictures.