The protests over the crackdown started last evening.
The ruling BJP today appealed to the Sikh bodies to "isolate" Khalistani supporters as the search for Amritpal Singh entered its third day.
Manjinder Singh Sirsa, the party's prominent Sikh leader, told reporters that everybody must condemn the London incident in which some Khalistani supporters pulled down the national flag from the Indian High Commission building in London.
The foreign ministry summoned the senior most diplomat of UK in New Delhi late last evening and demanded an explanation for "absence of security" at the high commission premises.
The UK government's "indifference" to Indian diplomats and personnel was "unacceptable", the statement read.
The protests over the crackdown against Amritpal Singh started last evening. Cellphone videos posted on social media showed protesters climbing the building and taking down the Indian flag.
In Australia's Brisbane, pro-Khalistan groups carried out what they called a referendum on Khalistan.
Four of Amritpal Singh's top aides, arrested and flown to Dibrugarh in upper Assam, have been charged under the stringent National Security Act (NSA), which allows the police to detain suspects in any prison across the country.
Intelligence reports suggest that Amritpal Singh was using drug rehab centres and a gurdwara to stockpile weapons and was preparing youths to carry out suicide attacks.
The crackdown comes a month after Amritpal Singh and his supporters broke into a police station with swords and guns for the release of one of his aides. Six policemen were injured in the clash.
Sources say Punjab Chief Minister Bhagwant Mann had discussed the plan to arrest Amritpal Singh with Home Minister Amit Shah in a meeting on March 2.
So far, the police have arrested over 110 associates of Amritpal Singh. Several members of his 'Waris Punjab De' group have also been detained for questioning.