The Treasury Department was accused of breaking federal law by giving Elon Musk’s team of government efficiency enforcers access to a trove of personal and financial information — setting up a legal showdown over the Trump administration’s signature effort to shrink the government.

U.S. Sen. Elizabeth Warren demanded answers following reports that billionaire Elon Musk took access to the nation's finance system, including sensitive financial data of nearly all Americans.

In a letter to the Treasury secretary, the Democratic senator warned against meddling with a system that processes trillions of dollars of transactions.