With several fraud cases worth thousands of crores of rupees surfacing in Indian banks, the banking sector gone into a "deep crisis" with credibility at all time low due to failure of regulatory oversight, Congress said on Friday."Unimaginable sums of thousands of crores have been looted by select few by faking letters of undertaking (LoUs), not paying loans and fraudulent means under a complicit banking system," party spokesman Randeep Singh Surjewala told media persons here.About Rs 61,000 crores was swindled through the 11 banking fraud cases that were uncovered over the past few months, he said."India's banking sector is in deep crisis due to the undermining of integrity of regulatory institutions and the failure of regulatory oversight."Accusing Prime Minister Narendra Modi of being on an indefinite vow of silence, Surjewala said under his "direct watch", the duping, loot, cheating and swindling of banks were taking place."'A scam a day' and 'Let the looters run away' were the slogans of the Modi government."People's money was allowed to be brazenly looted by the likes of (liquor baron) Vijay Mallya, (former Indian Premier League Chairman) Lalit Modi and (Punjab National Bank fraud accused diamantaire) Nirav Modi, who were all allowed to flee the country," the Congress leader said.As a result of the scams, the gross non-performing assets (NPAs) of the banking sector in the country have tripled, he alleged, adding that there isn't any bank in the country that is unaffected by the scams.Attacking the Modi government, he said it has been in deep slumber and has also refused to acknowledge publicly the "looting and duping" of common man's money by Nirav Modi and his uncle Mehul Choksi through Ponzi gold schemes.Even as the frauds were piling up, the PM and Finance Minister Arun Jaitley were maintaining their deafening silence, Surjewala added.