The US Justice Department has charged an Indian intelligence official this week in connection with a foiled plot to kill a Sikh separatist leader living in New York City.
The suspect, who remains at large, is the second Indian national to be charged with conspiring to murder Gurpatwant Singh Pannun, a US-Canadian citizen who is one of the main voices of the Khalistan movement.
The Khalistan movement is pushing for an independent Sikh nation carved out of territory that currently belongs to India and Pakistan.
"The FBI will not tolerate acts of violence or other efforts to retaliate against those residing in the US for exercising their constitutionally protected rights," said FBI Director Christopher Wray.
The US said Indian authorities had cooperated with investigations.
"They did inform us that the individual who was named in the Justice Department indictment is no longer an employee of the Indian government," State Department spokesman Matthew Miller told reporters before the case was unsealed.
"We are satisfied with cooperation. It continues to be an ongoing process."
Sikh separatist undeterred by threats
The public naming of the suspect on Thursday came days after Canada expelled six diplomats, including the high commissioner, over alleged links to attacks against Sikh leaders in the country.
India retaliated by expelling six Canadian diplomats.
As international tensions rise over the issue, Pannun said the alleged assassination plots against Sikh leaders in North America would not stop the Sikh independence movement.
"This is not going to deter me from running my global Khalistan referendum campaign," Pannun told DW's Washington correspondent Ines Pohl in an interview.
He also accused India of hiring multiple "hitmen" from within the Sikh community. The Indian government has denied accusations that it was involved in the alleged plots.