New Delhi: Amid the multi-agency probe into the Punjab National Bank (PNB) scam, the state-run bank on Monday 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 jeweler Nirav Modi and associates had allegedly acquired fraudulent letters of undertaking (Lou) from one of the branches of the PNB for overseas credit from other Indian lenders.

In a filing to the BSE late Monday night, the bank said the number of unauthorized transactions could go up by more than Rs 1,300 crore. "...We have to inform that quantum of reported unauthorized transactions can increase by $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 14 February when it first disclosed the fraud and at that time, the "fraudulent and unauthorized transactions" was estimated at $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.