Organizers of an unofficial worldwide referendum on Punjabi independence have added a question to the ballot in British Columbia asking if India's high commissioner was responsible for the killing of a prominent provincial Sikh leader in June.
The group Sikhs for Justice, which has been staging a series of non-binding votes in several countries on the independence issue, says the first stage of balloting in B.C. on Sunday attracted more than 135,000 voters.
It says the second stage will be held on Oct. 29 and will add a second question about whether High Commissioner Sanjay Verma was responsible for the "assassination" of Hardeep Singh Nijjar.
Police say Nijjar's death has not been connected to foreign interference.
The Sikh independence movement has angered India's government, with Prime Minister Narendra Modi expressing "strong concerns" to Prime Minister Justin Trudeau about Canada's handling of the issue.
Nijjar, who was a strong supporter of an independent Sikh homeland known as Khalistan, was gunned down outside the Guru Nanak Sikh Gurdwara in Surrey, B.C., on June 18.
Homicide investigators have said they are seeking two "heavy-set" gunmen and the driver of a getaway car, a silver 2008 Toyota Camry.
The killing prompted protests outside Indian consulates and accusations of foreign involvement in the murder.
India's Ministry of External Affairs said in a statement that Modi told Trudeau on the sidelines of last weekend's G20 summit in New Delhi that progress in the countries' relationship required "mutual respect and trust."
The statement said Modi expressed strong concerns about "continuing anti-India activities of extremist elements in Canada."
It said the Sikh movement was "promoting secessionism and inciting violence" against Indian diplomats, and called on Canada to work with India on what New Delhi said was a threat to the Canadian Indian diaspora.
Voting in the referendum on Sunday was held at the gurdwara where Nijjar was killed, and will be conducted there again next month.