London: Britain said on Tuesday that it was in close touch with its Canadian counterparts regarding "serious allegations" from Ottawa that the Indian government played a role in the assassination of a Sikh separatist leader in Canada, reported.

"We are in close touch with our Canadian partners about these serious allegations," a UK government spokesperson was quoted as saying by the news agency.

"It would be inappropriate to comment further during the ongoing investigation by the Canadian authorities."

Canada said on Monday it was "actively pursuing credible allegations" that linked Indian government agents to Hardeep Singh Nijjar's murder in British Columbia in June, according to the report.

Meanwhile, India rubbished the allegations as "absurd and motivated" and urged Canada instead to take cognizance of anti-Indian elements operating from its soil and take legal action.

Canada also expelled India's top intelligence agent in the country, while New Delhi expelled a Canadian diplomat, according to the report.

A statement issued by India's Ministry of External Affairs reads, "The High Commissioner of Canada to India was summoned today and informed about the decision of the Government of India to expel a senior Canadian diplomat based in India. The concerned diplomat has been asked to leave India within the next five days.

"The decision reflects the Government of India’s growing concern at the interference of Canadian diplomats in our internal matters and their involvement in anti-India activities."

India's Ministry of External Affairs issued a statement and said the allegations made by the Canadian government were 'absurd and motivated'.

"Similar allegations were made by the Canadian Prime Minister to our Prime Minister and were completely rejected," read the statement issued by the MEA.

"We are a democratic polity with a strong commitment to rule of law. Such unsubstantiated allegations seek to shift the focus from Khalistani terrorists and extremists, who have been provided shelter in Canada and continue to threaten India’s sovereignty and territorial integrity. The inaction of the Canadian Government on this matter has been a long-standing and continuing concern," read the statement.

"That Canadian political figures have openly expressed sympathy for such elements remains a matter of deep concern.The space given in Canada to a range of illegal activities including murders, human trafficking and organised crime is not new.We reject any attempts to connect the Government of India to such developments," the statement said.

Who was Hardeep Singh Nijjar?

Hardeep Singh Nijjar, a Canada-based pro-Khalistan leader, was shot dead in Surrey city, British Columbia province in June.

He had been a leading figure in the Khalistan separatist movement and was closely associated with Sikhs for Justice (SFJ).

Nijjar was also serving as the president of Guru Nanak Sikh Gurdwara in Surrey.

Nijjar, a member of the Khalistan Tiger Force (KTF), was a ‘wanted terrorist’ for his involvement in various acts of violence and subversive activities.