A man has been arrested after some pro-Khalistani groups vandalised the Indian High Commission in London and detached the Indian flag from the first-floor balcony of the building.
Videos on social media showed a crowd waving yellow "Khalistan" banners and a man detach the Indian flag from the first-floor balcony of the building, the BBC reported.
Two security guards were injured in the violent protest and an investigation has been launched.
PA news agency said that crowd members were believed to be supporters of a Sikh separatist movement.
Officers were called to the Indian High Commission at about 13:50 GMT on Sunday.
Upon arrival "the majority of those present had dispersed prior to the arrival of police", Metropolitan Police (Met) was quoted by the British broadcaster as saying.
The force's spokesperson said "windows were broken" and two members of security staff sustained minor injuries which did not require hospital treatment.
Responding to the incident, London's mayor Sadiq Khan said in a tweet: "I condemn the violent disorder and vandalism that took place at the Indian High Commission today (Sunday). There is no place in our city for this kind of behaviour."
An investigation has been launched by the Met, he added.
The British High Commissioner to India Alex Ellis described the incident as "disgraceful" and "totally unacceptable".