A US court has asked a human rights group to respond by Nov 4 to the US government's "suggestion of immunity" in a case against Prime Minister Narendra Modi for alleged crimes against humanity.

US federal Judge Analisa Torres Tuesday issued an order asking the American Justice Center (AJC) to file its response to suggestion of immunity for Modi filed by US prosecutor Preet Bharara's office on Sunday at the request of the State Department.

The State Department in a letter to the US justice department had conveyed the Indian government's request to have the case against Modi "dismissed on the basis of his immunity from jurisdiction as a sitting foreign head of government."

The letter by State Department legal advisor Mary McLeod to Acting Assistant Attorney General Joyce R. Branda is dated Sep 30, the day Modi had his formal summit meeting with President Barack Obama at the White House.

"The Department of State recognizes and allows the immunity of Prime Minister Modi as a sitting head of government from the jurisdiction of the United States District Court in this suit," McLeod wrote.

"This letter recognizes the particular importance attached by the United States to obtaining the prompt dismissal of the proceedings against Prime Minister Modi in view of the significant foreign policy implications of such an action," she added.

However AJC legal advisor Gurpatwant Singh Pannun contended that the 'suggestion of Immunity' filed by Bharara's office is not binding on the court as Modi's alleged human rights violations before becoming Prime Minister are not immune.

"The selective and arbitrary approach of the US Department of Justice on the issue of immunity to foreign leaders will be the key factor in challenging the immunity to PM Modi," he said.

The AJC case against Modi filed during his recent visit to the US seeks his prosecution under the Alien Tort Claims Act and Torture Victims Protection Act for his alleged role in the 2002 Gujarat riots when he was the state's chief minister.