New Delhi, Sep 15 (IANS) The Supreme Court Friday turned down a plea by a close relative of former External Affairs Minister K. Natwar Singh to release his passport that has been impounded due to his alleged involvement in Iraq's oil-for-food scam.

"Having considered the facts and circumstances of the case, it is not considered appropriate to make any interim order to permit the petitioner (Vipin Khanna) to leave the country," a bench of Chief Justice Y. K. Sabharwal and judge C.K. Thakker ruled.

"The petitioner will render full cooperation in the investigation and the ED (Enforcement Directorate) shall complete the investigation by October end," the bench directed.

"In case there is any threat to the NRI status of the petitioner, government of India shall extend its full cooperation," it added.

The ED had seized Khanna's passport as part of its probe into the involvement of Natwar Singh, his son Jagat Singh, and others in the Iraqi scam. Natwar Singh had resigned in November after a UN report referred to his involvement in the scam.

Appearing for Khanna, counsel Soli Sorabjee submitted he would cooperate with the investigation and was prepared to give an undertaking that he would return to India and would furnish security if he were allowed to leave the country.

Sorabjee argued that the petitioner's NRI status was under threat if he didn't return to Britain within 182 days. The ED had impounded Khanna's passport on May 5.

Sorabjee also said that the investigating agency, which was investigating allegations under the Foreign Exchange Regulation Act, was not competent to impound the passport under Section 10 (3) of the Passport Act.

Additional Solicitor General Gopal Subramaniam submitted that the petitioner was not cooperating in the investigation and his activities were of grave concern as they were prejudicial to national security.

He said the passport could not be released at this stage as the state apprehended the petitioner would tamper with the evidence in Britain if he were allowed to leave.