A senior British diplomat in Delhi has been summoned after a protest at the Indian High Commission in London.

Crowds gathered outside the building in Aldwych, Westminster, on Sunday and windows were broken.

The Indian foreign ministry issued a statement saying the senior diplomat had been asked to explain "the complete absence of British security".

After the protest a man was arrested on suspicion of violent disorder and a police investigation was launched.

The Metropolitan Police said two security guards were injured.

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.

Khalistan is the proposed name of a Sikh state separatist groups wants to create in the Punjab region, which spans both India and Pakistan.

The London protest took place as police in India searched for Amritpal Singh, a supporter of the Khalistan movement and self-styled preacher who has been on the run since Saturday. His supporters are accused of storming a police station last month.

He is considered a fugitive by the Indian authorities, and a massive search operation which has seen internet access suspended for millions is continuing.

The Indian foreign ministry said it expected the UK government to take "immediate steps" and to put security measures in place to prevent a similar incident happening again.

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", said the Met.

The force's spokesperson said "windows were broken" and two members of security staff sustained minor injuries which did not require hospital treatment.

The man who was arrested has been bailed until mid-June. The Met said inquiries were continuing.

Responding to the incident, London's mayor Sadiq Khan said he condemned "the violent disorder and vandalism that took place".

"There is no place in our city for this kind of behaviour", he tweeted.

The British High Commissioner to India Alex Ellis described the incident as "disgraceful" and "totally unacceptable".

Foreign Office minister Lord Tariq Ahmad of Wimbledon said he was "appalled" and the government would take the security of the Indian High Commission "seriously".

"This is a completely unacceptable action against the integrity of the Mission and its staff", he said.

(editor-in-charge：Press center5)