Senate Democrats are pushing to require President-elect Donald Trump’s Cabinet nominees to release their tax returns, something Trump refused to do during his campaign.

Currently the only Senate committees that can require such information are Finance, Budget, and Homeland Security and Governmental Affairs. But Democrats want to expand that authority to other committees that hold confirmation hearings, and plan to propose changing the rules when committees convene for the next Congress in January.

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Democratic ranking members of three committees said at a press conference Thursday that Trump’s nominees, especially those who are extremely wealthy, should be scrutinized for their financial dealings and potential conflicts of interests.

“We’ve never before seen a Cabinet like this that’s made up of so many wealthy insiders and big money interests,” said Michigan Democratic Sen. Debbie Stabenow, ranking member of the Agriculture Committee.

Democratic Sens. Ron Wyden, D-Ore., of the Finance Committee and Patty Murray, D-Wash., of the Health Education Labor Pensions Committee joined Stabenow at the Thursday press conference.

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Wyden said tax returns for nominees are reviewed by Republican and Democratic committee staff. If there appears to be an issue that the public should know about, the committee issues a detailed memo.

Finance Chairman Orrin G. Hatch, R-Utah, said he did not believe a mandate for other committees was warranted. “We don’t need to do that,” Hatch said, noting his panel already requests tax information from nominees for key slots like Treasury secretary. “Let’s face it. We’re talking about leading the world financially. We expect to get materials because we don’t want to make any mistakes, nor do we want to feel bad that we made a mistake.”Alan K. Ota contributed to this report.