The United States has said it will wait to see the results of the investigation announced by India concerning allegations of the involvement of an Indian official in a plot to assassinate a separatist Sikh leader in the US.

"We have noted at the most senior levels of this government – the secretary of state has raised this directly with his foreign counterpart that we take this issue very seriously. They told us they would conduct an investigation," State Department spokesperson Matthew Miller told reporters at his daily news conference on Tuesday.

"They have publicly announced an investigation. Now, we will wait to see the results of the investigation...," Miller said in response to a question.

American prosecutors have linked an Indian official to a man charged with conspiring to assassinate Sikh separatist Gurpatwant Singh Pannun on US soil.

India has described it as a "matter of concern" and asserted that follow-up action will be taken based on findings of a panel investigating the allegations.

The US, Miller said, has also urged India to cooperate with Canada's investigation of allegations of Indian involvement in the killing of a Canadian national.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.