Speaking to media after the Steering Committee meeting here, Rahul said, "such a fraud could not be done without a high-level protection."
"This Rs 22,000 crore scam cannot have been done without a high-level protection. It must have been known by the people in government beforehand otherwise it is not possible. Prime Minister will have to come forward and answer questions," he added.
PNB detected the alleged 11,400 crore rupee scam in which businessman Nirav Modi acquired fraudulent letters of undertaking from one of its branches for overseas credit from other Indian lenders.
Nirav Modi and his partner and Geetanjali Gems promoter Mehul Choksi are accused in the scam.
The scam was started in 2011 and was detected in the third week of January this year, after which the PNB officials reported it to the concerned agencies.
The Congress party has been cornering the Centre ever since the scam came to light while alleging that the fraud took place "under the nose of the NDA government." (ANI)