"Preliminary investigation reveals that Constable Javaid Ahmad had fired with his service rifle on the directions of In charge police party Assistant Sub Inspector Manzoor Ahmad, in violation of laid down standard operating procedure.
"Both the ASI and Constable have been arrested and further investigation is underway," a police spokesman said.
The arrests come nearly 11 hours after a teenage boy was killed in police firing at Narbal in Magam area of Budgam district during protests against killing of two youth in an army operation at Tral in Pulwama district earlier this week.
Suhail Ahmad Sofi and two other youth were injured in police firing at Narbal this morning during protests.
Sofi succumbed to injuries at a hospital.
"In this regard Case FIR No 34/2015 under sections 302 (murder), 147, 149, 341, 427 RPC was registered in Police Station Magam," the spokesman said.