Canada has expelled a top-ranking Indian diplomat over concerns that the Indian government may have been complicit in the killing of a Canadian citizen in British Columbia.

Hardeep Singh Nijjar was shot dead outside a Sikh temple in Surrey, B.C., on June 18. Nijjar, a supporter of an independent Sikh homeland, had been branded a wanted terrorist by the Indian government and was accused of leading a militant separatist group.

Canada has yet to provide any clear evidence. But Prime Minister Trudeau told Parliament that Canadian security agencies were investigating “credible” allegations of a potential link between agents of the Indian government and the killing of Nijjar, a Canadian citizen.

“Any involvement of a foreign government in the killing of a Canadian citizen on Canadian soil is an unacceptable violation of our sovereignty. We’ve been working closely and coordinating with our Allies on this very serious matter. I continue to urge the government of India to cooperate with Canada to get to the bottom of this matter.”

A White House statement said the U.S. was deeply concerned over the issue, and that it is critical that Canada’s investigation proceed, and that the perpetrators be brought to justice.

India immediately dismissed the accusations as absurd. But a few hours after Prime Minister Trudeau addressed Parliament, Canada’s Minister of Foreign Affairs, Melanie Joly, made her own announcement.

“The allegations that a representative of a foreign government may have been involved in the killing of a Canadian citizen on Canadian soil is not only troubling, but it is completely unacceptable. I’ve conveyed these principles to my Indian counterparts and, as of today and, as a consequence, we’ve expelled a top Indian diplomat from Canada.”

In response to the Canadian government’s diplomatic expulsion, the Indian government has now expelled one of Canada’s top diplomats from India.

India is ranked as a key player within the G20 nations. India is now the highest-populated country in the world and current ranks as the fifth largest economy. Shortly after Nijjar was killed, negotiations for a free trade agreement between India and Canada were put on hold. Both countries hoped to seal an initial deal this year. But a few weeks ago, Canada halted talks on the proposed trade deal with India.

Western allies have condemned alleged extra-territorial assassinations carried out by countries such as Russia, Iran, and Saudi Arabia. And they will not want India to join that list.