Washington (CNN) The top Democrat on the Senate Finance Committee is moving ahead with a threat to hold up any Treasury Department nominees over resistance from two agencies overseeing the release of President Donald Trump's personal tax returns.

"The administration's blanket obstruction of all oversight as it relates to Donald Trump's tax returns cannot go unanswered -- Congress needs to take action to force the administration to comply oversight," Oregon Sen. Ron Wyden said in a statement on Wednesday.

Trump has broken with decades of presidential precedent by refusing to make his personal tax information public, and has retained his interest in the Trump Organization while in office.

In late May, Wyden threatened to place a hold on nominees appointed by Trump, if Treasury Secretary Steven Mnuchin and Internal Revenue Service Commissioner Charles Rettig failed to adequately answer congressional requests.

Wyden said he has received "non-answers or no responses at all" from both of the agencies on questions about when political appointees learned of a memo prepared in anticipation of congressional request for Trump's tax returns among other queries. The IRS has yet to respond to the senator's request, which carried a June 11 deadline.

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