The White House declared on Monday that it considered the alleged involvement of the Indian intelligence agency in two assassination schemes in the US and Canada as a serious issue.

An Indian intelligence service officer was directly involved in an aborted plot to kill a U.S. citizen who happens to be one of Indian Prime Minister Narendra Modi's most outspoken critics in the United States, according to a report published in The Washington Post. According to the report, the officer was also involved in the Sikh activist's separate killing in Canada in June of last year.

The Indian foreign ministry said the report contained "unwarranted and unsubstantiated imputations on a serious matter", and that New Delhi was looking into the matter.

Foreign Ministry spokesman Randhir Jaiswal issued a statement, saying: "Speculative and irresponsible comments on it are not helpful."

"This is a serious matter, and we're taking that very, very seriously," White House spokesperson Karine Jean-Pierre told reporters. "We're going to continue to raise our concerns."

Also Read: RAW officer hatched plot to kill Khalistani activist Gurpatwant Pannun in US

Gurpatwant Singh Pannun, a Sikh separatist and dual citizen of the United States and Canada, was the target of an attempted murder plot, which was orchestrated by an Indian government official, according to U.S. officials in November.

India has expressed worry about the connection and distanced itself from the scheme, stating that it will formally look into the US concerns and take "necessary follow-up action" based on a panel's findings that was established on November 18.

Pannun is the general counsel for Sikhs for Justice, a group that India designated as an “unlawful association” in 2019 due to its radical activities. India subsequently designated Pannun as an "individual terrorist" in 2020.

Given their shared concerns about China's rising influence, India and the Biden administration in the US are trying to forge closer ties, so both parties must tread carefully on this issue.

The U.S. plot was revealed two months after Canada declared it was investigating plausible claims that may associate Indian operatives with the June killing of another Sikh separatist, Hardeep Singh Nijjar, in a suburban area of Vancouver.

India vehemently denied Ottawa's allegations.