British foreign minister James Cleverly on Wednesday said the country will review security at the Indian High Commission in London following “unacceptable acts of violence” towards the mission’s staff.

Earlier this week, India summoned the most senior British diplomat in New Delhi to protest at the actions taken by “separatist and extremist elements” against the country’s mission in London.

The BBC and Indian media reported that protesters with “Khalistan” banners detached the Indian flag from the first-floor balcony of the diplomatic mission’s building earlier, to protest against the recent police action in India’s Punjab state.

Khalistan refers to an independent Sikh state sought by some groups but which does not exist.

According to the BBC, crowds had gathered outside the high commission’s building on Sunday and windows were broken, after which India demanded an explanation for the “complete absence of British security” around the premises.

On Wednesday, Indian daily The Hindu reported that at least a hundred police officers were standing guard on both sides of the road outside the High Commission in London on Wednesday.

Cleverly said that a police investigation was ongoing after the acts of violence and that the country will make the necessary changes to ensure the safety of the Indian mission’s staff as it did for demonstrations on Wednesday.

Authorities in India’s northern state of Punjab had also launched a major search on Saturday for Singh, who has risen to prominence in recent months demanding the creation of Khalistan, a separate Sikh homeland.

On Monday, Indian authorities had extended a mobile internet blackout across a state of about 30 million people as police hunted a Sikh preacher, Amritpal Singh.

The same day, police said they had arrested 114 people so far but Singh’s whereabouts were unknown.