The US Justice Department last month charged an Indian citizen with plotting to assassinate a Sikh separatist leader on US soil, alleging an Indian government official was also involved in the planning.

“If someone gives us any information, we would look into it,” Modi said in his first comments on the issue.

“If a citizen of ours has done anything good or bad, we are ready to look into it. Our commitment is to the rule of law.”

India’s foreign ministry had earlier said it set up a “high-level” inquiry committee “to look into all the relevant aspects of the matter”.

On November 29, the US Justice Department unsealed murder-for-hire charges against Nikhil Gupta, 52, “in connection with his participation in a foiled plot to assassinate a US citizen” of Indian origin in New York City, it said in a statement.

The Justice Department said the man allegedly targeted in the killing “is a vocal critic of the Indian government and leads a US-based organisation that advocates for the secession of Punjab,” a northern Indian state with a large population of Sikhs.

Gupta, who lives in India, was arrested by authorities in the Czech Republic under US extradition orders.

Modi’s comments come after the White House said it was treating an alleged plot to assassinate a Sikh separatist in the United States with “utmost seriousness,” and had raised the issue with the Indian government.

The Financial Times reported that same day that US authorities had thwarted a conspiracy to kill Gurpatwant Singh Pannun, a US and Canadian citizen.

Canada and India had a major diplomatic row after Canadian Prime Minister Justin Trudeau in September linked New Delhi to the June killing of Canadian citizen Hardeep Singh Nijjar, also a Sikh separatist.

New Delhi called the Canadian allegations “absurd.”

Modi also told the Financial Times that India was “deeply concerned about the activities of certain extremist groups based overseas”.

He added that “these elements, under the guise of freedom of expression, have engaged in intimidation and incited violence”.