New Delhi: Amid the multi-agency probe into the PNB scam, the state-run bank today said the amount of fraudulent transactions could be Rs 1,300 crore more than the current estimate of about Rs 11,400 crore.

The latest announcement from the public sector lender assumes significance against the backdrop of the probe going on into the Rs 11,400 crore scam, which is already one of the biggest in the Indian banking sector.

On February 14, the bank had detected the fraud wherein billionaire jeweller Nirav Modi and associates had allegedly acquired fraudulent letters of undertaking (LoUs) from one of the branches of the PNB for overseas credit from other Indian lenders.

In a filing to the BSE late tonight, the bank said the amount of unauthorised transactions could go up by more than Rs 1,300 crore.

"...We have to inform that quantum of reported unauthorised transactions can increase by USD 204.25 million (approximately)," the filing said.

At the current exchange rate, the amount comes to around Rs 1,323 crore.

The bank also referred to its filing made on February 14 when it first disclosed the fraud and at that time, the "fraudulent and unauthorised transactions" was estimated at USD 1.77 billion (about Rs 11,400 crore).

The scam was perpetrated by way of fraudulent Letters of Undertaking (LoUs) generated in the name of Punjab National Bank.