WASHINGTON – House Republicans joined Democrats on Tuesday in warning the FBI that it could lose the power to demand that companies turn over customers’ telephone, e-mail and financial records if it did not swiftly correct abuses in the use of national security letters, the investigative tool that allows the bureau to make such demands without a judge’s approval. The warnings came at a hearing of the House Judiciary Committee into a recent report by the Justice Department’s inspector-general, Glenn A. Fine. The report found that the FBI had repeatedly violated the rules governing the letters, sometimes by invoking emergency procedures to exercise them when there was no emergency, and had bungled record-keeping so badly that the number of letters exercised was often understated when the bureau reported on them to Congress. “I just want to convey to you how upset many of us are who have defended this program and have believed it is necessary to the protection of our country,” Rep. Dan Lungren, R-Calif., told Valerie E. Caproni, the bureau’s general counsel. If the handling of national security letters is not improved soon, added Lungren, a former California attorney general, the bureau will not “have to worry about improving your procedures for NSLs because you probably won’t have NSL authority.” 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! Rep. Darrell Issa, R-Calif., said he was “shocked” by the bureau’s transgressions and suggested that they might have broken the law. “If what was done was done by a private-sector individual, wouldn’t the FBI be arresting them?” Issa asked. “Wouldn’t the U.S. attorneys be prosecuting people who played fast and loose with these rules?” Fine replied that the question of whether laws were broken “depends on the intent involved and what happened.” He said that while his investigation had found sweeping problems resulting from “mistakes, carelessness, confusion, sloppiness, lack of training, lack of adequate guidance and lack of adequate oversight,” it had not found proof of deliberate wrongdoing. Caproni did not take issue with the findings. “I can tell you that we’ve had a lot of soul-searching at the FBI” since the inspector-general placed “an F on our report card,” she said. Caproni said officials of the bureau believed that the problems might result in part from the secrecy that cloaks the use of national security letters, which are exercised most often in counterterrorism investigations.