The day-long search operations were carried out at a number of RIL premises in Delhi, including its corporate office in Mumbai, in connection with the case relating to alleged recovery of "top secret documents" from Balasubramaniam's office premises, official sources said.

Confirming the development, CBI sources told The Financial Express that a team consisting of 50-55 people led by DIG RC Arora from CBI's central unit at Delhi carried out search operations covering the offices and residence of Ambanis.

According to CBI sources, around 25 to 30 personnel from the CBI headquarters at Tanna House located in south Mumbai and Bank and Securities Fraud Cell officials were deployed to carry out the searches.

Later in the evening, the companyconfirmed the searches by way of a press release, but held corporate rivals responsible for the action. The release, quoting a Reliance spokesperson, said: "A CBI team visited various Reliance offices and residences in Mumbai and Delhi in connection with a case registered under the Official Secrets Act (OSA) in Delhi against a company official, V Balasubramaniam."

According to the RIL communique, the company officials and staff extended full cooperation to these teams. Nothing incriminating was found in the course of these searches in Mumbai and Delhi.

"Reliance has never obtained or used any documents or information covered by the provisions of the OSA for any purpose," the release said, adding that "allegations and misinformation to the contrary are being continuously unleashed on the media by our known corporate rivals".

"Reliance welcomes a full, free and fair investigation, which will manifestly clear Reliance of all such allegations", it concluded.

The CBI had registered a case, followingalleged recovery of "top secret documents"' during searches conducted by the Delhi police in connection with cases against Romesh Sharma, suspected frontman of Dubai-based don Dawood Ibrahim, at Balasubramanian's office premises here.

The case involving Sharma was handed over to the CBI earlier this month following recovery of some government documents and computer floppies by the Delhi police during searches in the office and residential premises of Balu.

Balasubramanian had, however, denied that any papers relating to union cabinet decisions or any other secret official documents had been seized from him by the police.