NEW DELHI - Indian police have opened an investigation into a protest this week outside its High Commission in London, partner ANI reported on Friday, pursuing action on an incident that has raised tension in relations with Britain.
Protesters with "Khalistan" banners took an Indian flag down from a first-floor balcony of the High Commission in the British capital on Sunday to denounce recent police action in India's Punjab state, British and Indian media reported.
Khalistan is the name of an independent Sikh homeland that some members of that community aspire to, both at home in India and in countries where Sikhs have settled.
India summoned the top British diplomat in New Delhi on Sunday to convey its "strong protest at the actions taken by separatist and extremist elements" at the mission, and to seek an explanation for "the complete absence" of security there.
British Foreign Secretary James Cleverly said acts of violence towards staff at the High Commission in London were unacceptable and British police were investigating.
Indian police had also opened an investigation, the ANI news agency reported.
"Case registered after the Ministry of Home Affairs asked Delhi Police to take appropriate legal action," ANI said, citing the police department of the Indian capital that reports to the federal government.
Police officials and the British embassy in New Delhi did not immediately respond to calls and messages seeking comment.
Sikh militants complaining of unfair treatment on the part of the central government and seeking an independent homeland waged an anti-government campaign in the 1980s and early 1990s in which tens of thousands of people were killed.
Police in Punjab, where Sikhs are in the majority, this month launched a hunt for a Sikh preacher who has revived talk of an independent homeland.
(Reporting by Sakshi Dayal; Editing by Robert Birsel)