Updated at 7:57 p.m. ET

White House officials questioned whether President Trump might be breaking the law when he ordered military assistance for Ukraine frozen in July, according to transcripts released on Tuesday by House Democrats.

A career official with the Office of Management and Budget told impeachment investigators that he wasn't given details about why millions of dollars for Ukraine should not be paid — but he observed to superiors that the move would raise big legal questions.

Mark Sandy, deputy associate director for national security within the Office of Management and Budget, talked with impeachment investigators behind closed doors on Nov. 16.

The transcript of his deposition was released on Tuesday along with that of Philip Reeker, a top State Department official.

An OMB attorney was said to have resigned at least in part over concerns about the need to follow the law, Sandy told investigators. A second OMB employee also resigned in September, Sandy said, after expressing "frustrations about not understanding the reason for the hold."

In Sandy's case, he described receiving an email on July 12 from a supervisor that announced Trump wanted to hold up military-support funding for Ukraine.

No other country was mentioned and no explanation was included, according to the transcript. The message Sandy took away in so many words was: Stop the assistance now, and then you may learn why later.

" 'Let the hold take place' — and I'm paraphrasing here — 'and then revisit this issue with the president,' " was how Sandy described a conversation between two other White House officials.

No explanation was offered about freezing the assistance until September, Sandy said, when he remembered seeing an email about Trump's concern that other allies weren't contributing enough to Ukraine's defense.

Allegations about abuse of power

Sandy's testimony is important to Democrats' argument that Trump used his power capriciously — the president did not say in real time, according to this account, that he was worried about corruption in Ukraine and wanted to freeze assistance until he was satisfied with reforms there.

That has been among explanations that the White House and others have since given about why Trump acted as he did. What Sandy's testimony illustrated was that no explanation was given in real time.

Moreover, critics argue, the law obligates Trump to dispose of funds in whatever way Congress designates. Sandy told investigators that when he learned of the hold, he warned about its implications under the 1974 Impoundment Control Act.

The funds Trump wanted to freeze had to be used by Sept. 30, Sandy said. If they weren't, "they basically expire and they return to the Treasury."

A new summary released by the House Budget Committee earlier on Tuesday describes how the first official act to stop $250 million in security assistance took place on July 25 in a letter signed by an OMB official.

Democrats on the House and Senate Appropriations committees warned the Trump administration in an Aug. 3 letter that any such hold could constitute an "illegal impoundment" of funds, the new document says.

That echoed the concerns that Sandy said he and some colleagues voiced inside the administration.

Ultimately, the White House released the Ukraine assistance in early September. Trump and aides had wrought a policy over the year aimed on extracting concessions from Ukraine's leader.

In exchange for a meeting and the military assistance, witnesses have said, Trump wanted Ukraine's president to announce investigations that Trump thought might help him in the 2020 election.

Ukrainian President Volodymyr Zelenskiy never made such a commitment.

Nonetheless, Democrats call the actions in the Ukraine affair an abuse of power that could merit impeachment. House Judiciary Committee Chairman Jerry Nadler, D-N.Y., said on Tuesday that he plans to convene the next hearing in the process on Dec. 4.

Defenders: All's well that ended well

Republican defenders argue that the totality of Trump's actions on Ukraine over this year show there was no improper exchange. Trump's allies reject Democrats' claims of "attempted bribery" or "attempted extortion."

Trump maintains that his July 25 phone call with Zelenskiy was "perfect."