WASHINGTON — Career diplomat Phillip Reeker told Congressional investigators behind closed doors what he knew about the ouster of Ambassador Marie Yovanovitch, according to a source with direct knowledge of his testimony Saturday in the impeachment inquiry.

Yovanovitch, a well-respected expert on Ukraine, has said that she was fired by the direction of President Donald Trump at the recommendation of Rudy Giuliani.

Reeker told Congressional investigators that he and his colleagues in the European Bureau at the State Department attempted to put out a proactive statement in support of Amb. Marie “Masha” Yovanovich but they were told by Undersecretary David Hale to not issue it, according to a person familiar with his testimony.

Reeker said he was “disappointed” that there would be no public show of support for Yovanovich and provided investigators with more details about “the circumstances involving Yovanovich,” according to two people familiar with his testimony Saturday in the impeachment inquiry.

Reeker’s superior was Hale who reported to Ulrech Brechbuhl, counselor and close ally to Secretary of State Mike Pompeo.

Yovanovitch, a well-respected expert on Ukraine, has said that she was fired by the direction of President Donald Trump at the recommendation of Rudy Giuliani.

Reeker also testified that he became aware that nearly $400 million of military aid was being withheld from Ukraine in late July, but he never knew why. Reeker also said he was aware that a White House meeting between Presidents Trump and Zelensky was "delayed," but didn't know why that was either.

Reeker also testified that Amb. Volker was communicating with Giuliani, according to a person familiar with his testimony.

In his testimony, Reeker, who oversaw Ukraine policy at the State Department, provided investigators with a thorough testimony, referring to a three-inch binder throughout the question and answer session that lasted more than eight hours in a rare Saturday session, according to lawmakers. He also corroborated what previous witnesses have said, according to both Republicans and Democrats who sat in the session.

Rep. Mark Meadows, R-N.C, said that Reeker’s deposition echoed previous testimony from former U.S. envoy to Ukraine Kurt Volker.

“When we look at what Ambassador Volker said, the very first witness to come in, and take it through the witnesses that we've had today, it becomes much more clear that the promise or leverage of foreign aid for some kind of political favor was more chatter and certainly was not supported by any directive or edict,” Meadows said.

Reeker also discussed the “three amigos” — European Union Gordon Sondland, Volker and Energy Secretary Rick Perry, the president’s confidantes — that the administration put in charge of Ukraine policy after Yovanovitch was recalled from her position in May, Meadows said.

Reeker said he didn’t have direct knowledge of what Secretary of State Mike Pompeo knew about the ouster of Yovanovich or why the military aide was being withheld, according to a person familiar with his testimony.

Democrats indicated that Reeker knew more than they had anticipated. He was “a reservoir of information,” Rep. Steven Lynch, D-Mass., said.

But Republicans largely dismissed the significance of his testimony.

“I don’t see him as being directly involved with first-hand knowledge.I don’t see him being directly involved,” said Meadows, who noted that Reeker offered “meticulous” testimony and often referred to a 3-inch binder he brought with him.

Reeker, who began his post in March, spent his first week reacting to what he called a “fake narrative” being spread about Yovanovich, which previous witnesses have testified was run by President Donald Trump’s personal lawyer Rudy Giuliani.