India has summoned Canada's top diplomat in New Delhi to voice its discontent with protests by supporters of a Sikh separatist which took place outside its mission headquarters in Vancouver on Saturday.

Hundreds of supporters of fugitive Sikh separatist Amritpal Singh demanded an independent Sikh state, Canadian media reported. 

Delhi said on Sunday it was concerned with how the protesters were purportedly allowed to breach the security of its diplomatic mission.

"It is expected that the Canadian government will take all steps which are required to ensure the safety of our diplomats and security of our diplomatic premises so that they are able to fulfill their normal diplomatic functions," India's Ministry of External Affairs said in a statement.

Canada has one of the largest Sikh communities in the world outside India. 

Who is Singh and why is he prompting protests?

Singh, a radical Sikh preacher, rose to prominence recently after reviving the long lost dream of creating Khalistan, a separate Sikh homeland. He has held rallies in rural pockets of Punjab where he shared his hardline interpretation of Sikhism.

Indian authorities launched a manhunt for Singh over a week ago. Some 100 others have also been arrested.

The northern state of Punjab has meanwhile experienced mobile internet cuts and a ban on gatherings of more than four people in some parts.

Police have accused Singh and his supporters of attempted murder, obstruction of law enforcement, and causing disharmony.

Indian authorities have long rejected calls for an independent Sikh state, in fear of reviving the violence which killed tens of thousands of people in the 1980s and early 1990s.

Last week, Indian police opened an investigation into a protest at its High Commission in London, where protesters gathered to denounce the police action in Punjab. Holding "Khalistan" banners, protesters took down an Indian flag from a balcony of the commission.

Delhi has also registered its "strong protest" with the US State Department, after another pro-Singh protest outside the Indian Consulate in San Francisco.

rmt/wd (AFP, Reuters)