Trudeau has become embroiled in a fresh spat, following his apparent endorsement of allegations that factions within the Indian government had actively sought to undermine his visit to the country last week.
The comments, made during Trudeau's first parliamentary session since returning to Canada, provoked a swift rebuke from the Indian government, with a spokesman for India's foreign ministry labeling the suggestion "baseless and unacceptable."
The dinner invitation, which was later withdrawn, sparked outrage in parts of India, where the issue of Sikh separatism remains a highly charged and emotive topic.
In response, Trudeau appeared to offer his support to the claims made in the reports. "When one of our top diplomats and security officials says something to Canadians, it is because they know it to be true."
"The Government of India, including the security agencies, had nothing to do with the presence of Jaspal Atwal at the event hosted by the Canadian High Commissioner in Mumbai or the invitation issued to him for the Canadian High Commissioner's reception in New Delhi. Any suggestion to the contrary is baseless and unacceptable," said India's Ministry of External Affairs in a press statement released Wednesday.
Atwal scandal
It remains unclear how Atwal, a known militant who in 1987 was sentenced to 20 years in a Canadian court for his part in the attempted murder of a visiting Indian state minister, managed to obtain a visa to enter into India.
Atwal was one of four men who ambushed and shot Malkiat Singh Sidhu, a then-member of Punjab's cabinet, who was visiting Canada for a relative's wedding, badly wounding him.
In the sentencing, the judge called the crime "an act of terrorism in order to advance a cause."
Canada is home to about 468,000 Sikhs, comprising 1.4% of its population. A small but influential number of those Sikhs support the idea of Khalistan, or the demand for a separate state for Indian Sikhs.
The separatist issue goes back decades in India, with one of the most important clashes occurring in 1984 when Indian Army soldiers stormed the Golden Temple in Amritsar, Sikhs' holiest site, in an effort to capture separatist leaders.
In 1985, the violence spilled over into Canada, when Sikh separatists bombed an Air India plane that had taken off from Toronto airport, killing all 329 people aboard, including numerous Canadians of Indian descent. The only person who was convicted in the bombing was released in 2017 by Canadian courts after two decades in jail.
An armed Sikh rebellion operated in Punjab, the heartland of the faith, from the 1980s to the early 1990s, when it was crushed. Today, pockets of support remain in parts of the Sikh diaspora, including in Canada.
Trudeau has actively courted the Sikh vote, previously proclaiming that his cabinet has more Sikhs than Modi's. Analysts say a particular area of contention during Trudeau's India visit, was his appearance at a Sikh event in Toronto last year, where separatist flags and posters depicting an extremist Sikh leader killed in the 1984 Indian Army operation were displayed.