The letter disputes the validity of the investigation, claiming that the request was for confidential communications "potentially protected by the privilege of the executive and which would require careful review."
Bernison concludes by saying that the department "remains committed. to work with Congress. "
The role of Secretary of Energy Rick Perry in the scandal with Ukraine has come under scrutiny in recent weeks and his contact with Ukrainian officials has been called for by House Democrats.
White House Chief of Staff Mick Rarely Thursday's news conference Mulvani confirmed that President Donald Trump instructed Perry at a May 23 meeting in the Oval Office to work through his personal lawyer, Rudy Giuliani, on Ukraine-related issues.
Multiple witnesses in the impeachment trial have evidence that Giuliani is interfering in foreign policy related to Ukraine, circumventing the diplomatic process in some cases.
Democrats from the House also sought documents related to Perry's trip to Ukraine to take office as President Vladimir Zelensky, when Perry led the US delegation in place of Vice President Mike Pence at the behest of Trump.
The rejection is the latest instance in which the Trump administration has called for House Democrats to investigate barley.
The White House has accused a letter to Parliament Speaker Nancy Pelosi last week that its impeachment inquiry is "illegitimate" and "unconstitutional" and that it will not participate in the investigation.
The Department of State, the Pentagon and the Office of Management and Budget were no longer able to meet the deadlines for a homeowner summons after Democrats requested multiple documents related to freezing US security aid in Ukraine, prompting Ukraine to open investigation and the ousting of former US Ambassador to Ukraine Marie Jovanovic.
"The Ministry is currently unable to comply with your request for documents," Robert Hood, Assistant Secretary of the Department of Defense for Legislative Affairs, wrote to the three committees leading the impeachment case on Tuesday. "The Department understands the importance of your request for information and has taken steps to identify, retain and collect potentially responsive documents."
Democrats have had greater success by using calls to attract current and former administration employees, despite the direction of The White House for not showing up. Last week, former White House adviser to Russia Fiona Hill, Deputy Assistant Secretary of State Department George Kent and US Ambassador to the European Union Gordon Sundland all testified.
But blocking the Trump administration's investigation hampered the democratic inquiry in a key way: these officials did not provide the committee with documents saying that they were the property of the Trump administration.
"We know from the additional witnesses who came out that there were additional documents that they provided to the State Department but were not provided to Congress," Homeland Intelligence Chairman Adam Schiff said this week. [1
"We will consider the challenge of summonses as evidence of the president's efforts to impede impeachment investigations. We can also use this obstacle as further proof of the president's fundamental misconduct, "Schiff wrote in a letter to colleagues this week.
Republicans defended the Trump administration's decision not to cooperate in the investigation, arguing that Schiff did not conduct
"I think the conference (Republican House) is completely united in the idea that we stand behind the president, as the American people do," said Ohio reporter Jim Jordan, most the highest Republican member on the House Oversight Committee. "This investigation, as I just said earlier, is dishonest and partisan, and we see what it is."
More calls are probably made from the Capitol Hill to the Executive Branch as the impeachment probe goes to more witnesses have been interviewed. While the Trump administration has rejected calls for documents, it remains to be seen whether senior officials Democrats are likely to seek testimony from – White House Chief of Staff Mick Mulvey, soon-to-be former Energy Secretary Rick Perry and former national security adviser John Bolton among them – will appear if summoned.
This story has been updated.