India's judicial authorities have "no jurisdiction" in the case involving Nikhil Gupta, Czech justice ministry spokesperson Vladimir Repka has said, days after his family approached the Supreme Court seeking its intervention in the matter.

Gupta, charged by the US government of involvement in a conspiracy to kill a Sikh separatist on American soil, has been in a jail in Prague since he was detained in the Czech Republic around six months ago.

The US has approached the Czech government for Gupta's extradition and proceedings relating to it are underway.

"Any judicial authorities of the Republic of India have no jurisdiction in the matter in question, the case is under the jurisdiction of the competent authorities of the Czech Republic," Repka said.

A family member of Gupta, 52, approached the Supreme Court last week pleading for issuing direction to the Indian government to intervene in the extradition proceedings and ensure a fair trial in the case.

The US federal prosecutors have charged Gupta of working with an Indian government employee in the foiled plot to kill US-based Sikh separatist Gurpatwant Singh Pannun, who holds dual citizenship of the US and Canada.

India has already constituted a probe committee to investigate allegations.

Repka also responded to allegations made in a petition filed in the Supreme Court by Gupta's family that he is not having adequate legal representation in the Czech Republic.

According to the applicable legislation of the Czech Republic, the defence counsel must always be representing a person against whom extradition proceedings are initiated, the spokesperson said.

"If a person does not have a defence counsel in cases where must have one, a defence counsel would be immediately appointed by the competent court," Repka told PTI in an email responding to a query.

"According to the available information, Nikhil Gupta is represented in the proceeding on his extradition to a foreign state by a defence counsel of his own choice, Petr Slepička," he said.

Repka said the Czech ministry of justice does not have any information, nor has received any complaints from Gupta or his defence counsel that he was not allowed to contact India's consular office.

He also dismissed allegations that Gupta was not being provided appropriate diet in the prison.

"Likewise, the ministry of justice of the Czech Republic does not have any information, nor has received any complaints that Nikhil Gupta has been provided with an inappropriate diet," Repka said.

On Thursday, External Affairs Ministry Spokesperson Arindam Bagchi said India received consular access on three occasions to Gupta and that necessary consular assistance is being extended to him.

"An Indian national is currently in the custody of the Czech authorities pending a request for extradition to the US. We have received consular access at least on three occasions," Bagchi said at his weekly media briefing.

"We are extending necessary consular assistance as per requirement," he said.

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