New Delhi: Soon after Khalistan supporters pulled down the national flag at the Indian High Commission building in London, videos of a huge mob was seen attacking the Indian Consulate in US's San Francisco while loud Punjabi music blared in the background. They also spray-painted a huge graffiti saying "Free Amritpal" on the outer wall of the building.

India has conveyed strong protest with the US over the incident and asked for appropriate measures to prevent recurrence of such incidents.

"The US Government was reminded of its basic obligation to protect and secure diplomatic representation. It was asked to take appropriate measures to prevent recurrence of such incidents," the government said in a statement.

Several videos, filmed by the attackers themselves, showed men smashing the glass on doors and windows of the consulate building with the wooden butt of the Khalistan flags they were earlier seen waving.

Three men, presumably employees of the Indian consulate, were seen removing the Khalistan flags put up in the building near the entrance when suddenly the mob broke through a barricade behind which they were earlier shouting slogans. Two men who were removing the flags then dashed inside the consulate, and a few protesters chased after them, flags in hand. Unable to get inside the building before the door was slammed shut in their faces, they could be seen violently hitting the doors and windows with the wooden sticks and rods of the flags. One of the men could be seen smashing the windows with a sword.

In Canberra, Khalistan supporters gathered outside Australian parliament to protest against the police crackdown on Amritpal Singh and his associates in Punjab.

Earlier today, a huge Tricolour was put up at the Indian High Commission building in London in response to the action by Khalistan supporters.

A photograph of the massive national flag stretched across India House in London's Aldwych has gone viral, with social media users applauding the move. Many praised the bold action by a High Commission official who is seen throwing the Khalistan flag out.

The External Affairs Ministry had summoned British deputy high commissioner Christina Scott late Sunday evening after the videos of the Indian flag being pulled down started circulating online. It demanded the arrest and prosecution of the pro-Khalistan people involved in pulling down the national flag.

The ministry also demanded an explanation for "absence of security" at the high commission premises and said the UK government's "indifference" to Indian diplomats and personnel was "unacceptable".

British officials condemned the vandalism, calling it "disgraceful" and "completely unacceptable". London Mayor Sadiq Khan tweeted, "I condemn the violent disorder and vandalism that took place at the Indian High Commission today. There is no place in our city for this kind of behaviour. An investigation has been launched by the Met into today's events".