Qasim, a Lashkar leader and terrorist, had planned the attack on a Border Security Force convoy in Udhampur on August 5.
An armed guard of Qatal was also killed in the attack that took place on Saturday night.
The encounter took place at Aribagh in Nowgam area on the outskirts of Srinagar, the official said.
Among the seizures made from the ultras included 2 kg RDX, a detonator and some hand grenades, Joint Commissioner of Police, Karnal Singh told PTI.
With terror groups misusing Aadhaar to camouflage the identity of their Pakistani cadres, the Jammu and Kashmir police will request the Unique Identification Authority of India (UIDAI) to strengthen safety features of the biometric ID, officials have said.
Top Lashkar-e-Tayiba commander Abu Qasim was gunned down on Thursday in Kashmir.
The final report against a juvenile who was also apprehended in the case will be submitted to the Juvenile Justice Board in Rajouri, a spokesperson of the federal agency said.
Inspector General of Police (IGP), Kashmir, Vijay Kumar said the police was tracking both the Pakistani terrorists from the day of the attack on the CRPF men on April 4, and the operation was launched on Sunday after pinpointing their location.
The encounter broke out as security forces were conducting search operations in Puchal area of Awantipora and hots were heard from nearby Goripora village, an official said.
As many as 160 terrorists were killed and 102 arrested in Jammu and Kashmir in 2019.
The Indian Army on Tuesday said the ceasefire violation along the Line of Control in Kashmir, which left two soldiers dead, was part of terrorists' plan to infiltrate into the Valley before the natural passes are closed by snowfall.
The security forces unearthed this information while interrogating the members of the twin modules busted by the police in Rajouri recently.
As the security forces were engaged in the counter-militancy operation, over 100 protesters pelted stones on them, an army official said.
Three army personnel were also killed in two encounters.
A 32-year-old man from Haryana's Mewat district has been arrested by Delhi Police for suspected links with Al Qaeda.