A cross-party group of parliamentarians has requested an urgent meeting with security minister Tom Tugendhat following reports of "threat to life warnings" being given to British Sikhs.
It comes following increasing concern about the treatment of Sikhs worldwide by the current administration in India.
Canada claimed India may be involved in the death of Hardeep Singh Nijjar, who was shot dead outside a temple in the Vancouver area in June 2023.
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The US department of justice last year alleged an Indian government official directed an unsuccessful plot to assassinate a Sikh activist in New York City.
There are also calls in the UK for an investigation into the death of Sikh activist Avtar Singh Khanda, who died in Birmingham after a sudden illness last year.
All three activists were on a "hit list" that appeared on the news in India, according to the politicians.
In a letter seen by Sky News, Labour MPs Preet Kaur Gill, Afzal Khan and Tanmanjeet Singh Dhesi, alongside Conservative Caroline Nokes and the SNP's Kirsten Oswald and Martin Docherty-Hughes all wrote to Mr Tugendhat, alongside Lord Tom Watson.
Ms Gill is also a shadow minister. Mr Dhesi had earlier asked the government in the House of Commons what they were doing to ensure the safety and security of British Sikhs.
The letter to Mr Tugendhat said: "This week, it was reported that several Sikhs living in Britain have been handed "Osman notices" by the police, warning them of threats against their lives.
"This comes amid increased tensions between the Indian government and its supporters and Sikh separatist activists, and following the news of the alleged extrajudicial killing of Sikh activist Hardeep Singh Nijjar in Canada and the plot by an Indian government employee to kill the Sikh attorney and activist Gurpatwant Singh Pannun on US soil last year.
"We are increasingly concerned by the stories that are being raised with us by our constituents and are seeking reassurance from the government that it is taking appropriate steps to support and protect the British Sikh community from any unlawful threats or attacks.
"You will be aware that last year an intelligence 'hit list' appeared on Indian broadcast news naming 20 Sikhs in the diaspora as 'enemies of the state', including the now deceased Hardeep Singh Nijjar as well as six British Sikhs.
"Several of these figures have received threats, harassment and intimidation since, with at least some under police protection in the UK.
"The sudden and untimely death of Avtar Singh Khanda in Birmingham last summer, who had also been threatened and accused in Indian media of pulling down the tricolour in the protest at the Indian High Commission despite a Metropolitan Police investigation finding otherwise, has also fuelled our concerns."
The letter adds: "We strongly believe that threats against the life of anyone, regardless of religion or belief, is abhorrent and must be met with strong condemnation and action to identify and bring perpetrators to justice.
"Members of the British Sikh community have expressed increasing concern that voicing their political views will make them targets, and we do not believe that is acceptable in a liberal and proudly multicultural democracy as ours.
"We are therefore writing to request an urgent meeting about threats against British Sikh community leaders and activists, and to seek your reassurance that the government is treating this issue with the seriousness it merits."
According to Sky's India reporter Neville Lazarus, the Khalistan movement - the campaign to have an independent, separate homeland for Sikhs in India - is a sensitive topic.
The movement has "died" in India, according to Lazarus, but has "survived in the West and in particular within the large Sikh diaspora in Canada".
He said: "There are regular referendums on Khalistan organised in Western countries, much to the disdain of the Indian government."
Narendra Modi's ruling Bharatiya Janata Party is widely seen as a Hindu nationalist movement.
A diplomatic row over the matter between the UK and India would further complicate the ongoing negotiations for a free trade agreement.
Jas Singh, an adviser to Sikh Federation UK, said at the time: "It's very concerning that the UK government is considering any action at the behest of a foreign government, all of which is designed to remove democratic civil liberties of UK residents.
"It is a legal right for individuals to campaign for an independent homeland, whether that's in the UK or abroad."
There were hopes at one point that a discussion could conclude this year, but it is now thought an agreement will not be reached before the next election.
Another major sticking point is the issue of visas and Indian workers being able to access the UK market.
The Home Office has been approached for comment.