The ISYF is supported by Pakistan's intelligence agency ISI.
Teams of National Disaster Response Force were trying to find out any person still trapped under the debris, officials said.
Singh, 27, was on the run since the blasts occurred at Liberty and Satyam theatres on May 22.
One person was killed and over 50 injured in the May 22 blasts at Liberty and Satyam cinema halls. Both theatres were screening the controversial Hindi film Jo Bole So Nihal.
India is experiencing its worst heat wave in 122 years.
The India-Pakistan Peace Cup snooker and a kabaddi series between the countries was cancelled owing to the 'tense' situation in the wake of the recent serial blasts in Mumbai.
The unidentified youths shot Nijjar, a designated terrorist, inside the premises of Guru Nanak Sikh Gurdwara Sahib, of which he was the head, at Surrey at 8:27 pm (local time) on Sunday, they said.
Pakistan's Inter-Services Intelligence is quite active in fomenting trouble in Punjab and the grenade attack in Amritsar was a pure act of terrorism, Singh said.
Even Congress MP from Ludhiana Ravneet Singh Bittu backed the policemen and praised them for their role during militancy and COVID-19 times.
In what is being seen as a veiled jibe at Punjab Congress president Navjot Singh Sidhu, CM Charanjit Singh Channi on Friday asked policemen not to bother about who says what and said criminals wet their pants on seeing them.
Following are some of the terror-related incidents that have taken place in Punjab between 2001 and 2016.
Punjab's Deputy Chief Minister Sukhjinder Singh Randhawa has said a probe would be carried out to ascertain whether Aroosa Alam, a Pakistani journalist who has been visiting former chief minister Amarinder Singh for several years, has links with the ISI.
Grewal, who was elected to the mayoral office in May 2005, said he will appeal UK PM Tony Blair to intervene.
"He was one of the oldest militant and wanted for several terror-related crimes," police told PTI.
The high-voltage campaign for the February 4 assembly elections in Punjab came to an end on Thursday evening following hectic campaigning by various political parties.
Punjab CM Amarinder Singh said that the 'possibility of involvement of ISI-backed Khalistani/Kashmiri terror groups can't be ruled out'.
The EC limits campaign expenses incurred by a candidate to Rs 50 lakh to Rs 70 lakh. But there is no such limit on spending for parties. The vendors aren't complaining.
'You bust one module and another one comes up.'
The assembly polls are seen as a test of Prime Minister Narendra Modi's popularity, especially in the wake of demonetisation.