"The current subpoena, however, raises a number of legal and practical concerns that must first be addressed," Hood said on Tuesday. "For example, although your letter asserts that the subpoena has issued 'pursuant to the House of Representatives' impeachment inquiry,' the House has not authorized your committees to conduct any such inquiry."
Earlier on Tuesday, Vice President Mike Pence and the White House Office of Management and Budget also refused to hand over documents related to the impeachment inquiry. Pence and the White House have both argued that the Democrats impeachment probe has not been authorized by a full House vote.
Trump lawyer Rudy Giuliani also defied his subpoena.
House Democrats launched their impeachment inquiry on September 24 to probe whether Trump tried to pressure Ukraine into investigating his political rival, Joe Biden. Lawmakers initiated the inquiry after a whistleblower sent a complaint to Congress, saying that Trump threatened to withdraw military aid to Ukraine if Kyiv failed to probe Biden and his son Hunter Biden.
The Trump administration has said it will not cooperate with the impeachment probe because the House did not hold a formal vote to authorize the inquiry.
Trump has denied any wrongdoing and has denounced the impeachment inquiry as a witch hunt aimed at reversing the outcome of the 2016 presidential election.