House Republicans are ratcheting up pressure on the Justice Department to end a federal investigation into consumer fraud that they claim is forcing banks to close the accounts of gun dealers, payday lenders and other legal businesses.

Republicans held two hearings this week on the legality of “Operation Choke Point,” a probe into whether banks and payment firms are enabling merchants to illegally withdraw money from consumer accounts to boost their own take from processing fees.

Prosecutors are focusing on activities, such as Internet gambling and small-dollar lending, that regulators say have high rates of complaints from customers about money being taken out of their accounts without their permission, an indication of fraud. Since 2012, the Justice Department has launched at least 15 criminal and civil investigations and has issued 50 subpoenas to banks and payment firms.

Critics of the operation have painted it as an attempt by the Obama administration to shut down legitimate businesses that it deems undesirable.

“There is an unacceptable level of collateral damage,” Rep. Bob Goodlatte (R-Va.) said at a House Judiciary hearing on Thursday. “There appears to be a disconnect between statements from top officials and what is happening in practice.”

He said the committee has received reports of banks severing relationships with law-abiding customers whose business activities are considered high risk by regulators. Goodlatte said he suspects that banks are responding to pressure from regulators who are acting in concert with the Justice Department.

Stuart Delery, assistant attorney general for the Justice Department’s civil division, told lawmakers that the department’s “policy is to investigate specific unlawful conduct based on evidence that consumers are being defrauded, not to target whole industries or businesses acting lawfully.”

Only one settlement has emerged from Operation Choke Point. It involved Four Oaks Bank of North Carolina, which was accused of waving off signs of fraud while raking in more than $850,000 in payment-processing fees and customer-refund requests. The bank allegedly let online lenders process $2.4 billion in illegal transactions. Four Oaks agreed to settle the case in January for $1.2 million.

Trade groups, nevertheless, insist the government is doing irreparable harm. The Community Financial Services Association of America, which represents payday lenders, filed a lawsuit last month against three banking regulators to stop “exerting back-room pressure on banks.”

At a House Financial Services hearing on Tuesday, officials from the Federal Reserve and the Office of the Comptroller of the Currency said their agencies are not involved in Justice’s operation. An official from the Federal Deposit Insurance Corp. said the agency has cooperated with prosecutors in their investigation of potential illegal activity.