(Reuters) - The U.S. justice department is exploring civil and criminal actions against more than 50 big and small banks that conduct business with payday lenders, who are being increasingly scrutinized by regulators, the New York Times reported, citing government officials. Under a new program, "Operation Choke Point," the department is checking banks over whether they enabled payday lenders to illegally siphon billions of dollars from U.S. consumers' checking accounts, the newspaper said, citing state and federal officials briefed on the investigation. In the first action under the program, federal prosecutors have already brought a lawsuit against Four Oaks Bank for being "deliberately ignorant" about processing payments on behalf of merchants, the report said. About $2.4 billion was illegally withdrawn from checking accounts of U.S. customers by companies enabled by Four Oaks Bank, the New York Times said. (http://link.reuters.com/rab46v) The bank later negotiated a civil settlement of about $1.2 million with federal prosecutors. However, a federal crackdown on banks remain tough as their role in siphoning off money is largely in the background with banking services being provided to third-party payment processors, who manage payments for their trading customers, the newspaper reported. The move has attracted criticism from congressional lawmakers, who accused the Department of Justice of trying to covertly quash the payday lending industry, according to the newspaper. The Department of Justice could not be immediately reached for comments outside of regular U.S. business hours. (Compiled by Shubhankar Chakravorty in Bangalore; Editing by Gopakumar Warrier)