IGP termed Abu Ismail's killing was a major achievement of security forces and severe jolt to Lashkar.
Several militant groups have sprung up, and Indian security forces have tried to wipe them out.
Two militants have been killed in a brief gunfight with government forces at Aribagh area of Kanipora in outskirt's of Srinagar City on Thursday late afternoon.
Ismail was the mastermind of the 10 July attack on a bus carrying Amarnath yatra pilgrims in south Kashmir's Anantnag district.
Sources told Sputnik that Abu Ismail was in Kashmir for past six months planning and executing major terror attacks including the Amarnath attack in July this year in which eight pilgrims were killed and many injured.
Lashkar has not only distanced itself from the attack on Amarnath pilgrims but also condemned the attack.More news: Jon Jones' UFC 214 win over Daniel Cormier has been overturned
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After his name figured as mastermind of the attack, Ismail was on run but under radar of the security forces, another police official said. "This Operation is a result of people's prayers".
Two foreign militants, both Pakistani nationals, were killed. After the death of Abu Dujana, Abu Ismail was given command of the LeT. "Priority is to eliminate militant leadership because they lure the youth to militancy", the IGP said. The other slain terrorist has been identified as Chota Qasim.
Ismail would be the fourth top militant leader killed in Kashmir since previous year. "He was also involved in other hit and run attacks", he said.
Vaid also said the encounter took place successfully with the support of the people, intelligence network and coordination between all forces. "The 50th battalion of Rashtriya Rifles did a good job", he said adding now there would be leadership vacuum in LeT.
The encounter ensued after a joint team of Police and 50 RR cordoned off the area following inputs about the presence of terrorists. He took over after the killing of Abu Dujana.
On the frequent internet shutdowns during and after encounters, Khan said that it was done because it was an operational requirement.