The Prime Minister's Office has refused to furnish data on documents and records it held on the mysterious disappearance of Netaji Subhas Chandra Bose, saying the disclosure would harm India's relations with foreign countries.

"On verification of the classified files held by PMO, it is held that their disclosure will prejudicially affect relations with foreign countries," Joint Secretary to the Prime Minister and Appellate Authority in the PMO Sanjay Mitra told Anuj Dhar of Delhi-based Mission Netaji, who sought the list under the Right to Information Act.

The PMO's denial comes close on the heels of Chief Information Officer A N Tiwari's warning to the Union Home Ministry that it would take stern action if the ministry did not furnish the 202 documents on Netaji under its possession.

Dhar, whose organisation is on a campaign to bring out the "truth" behind Netaji's disappearance, had earlier requested PMO's Central Public Information Officer Kamal Dayani to confirm if the PMO was holding classified records on Bose, and provide a list of all such records along with the unclassified ones.

In reply, Dayani provided a list of only the unclassified files, most relating to Bose's disappearance. In keeping with the RTI procedure, Mission Netaji reported the matter to the appellate authority in the PMO, complaining that Dayani's answer was "incomplete" because it has not responded to the request for the classified files.

Dhar, a journalist who has written Back from the Dead: Inside the Subhas Bose Mystery, said he would take up the matter with the Central Information Commission.