(CNN) President Donald Trump directed Secretary of Energy Rick Perry and two top State Department officials to deal with his private attorney Rudy Giuliani when the Ukrainian President sought to meet Trump, in a clear circumvention of official channels, according to two sources familiar with the conversation.

Trump believed Ukraine was still rampantly corrupt and said that if President Volodymyr Zelensky wanted to meet with him, Giuliani would have to be convinced first, one source said.

"If they can satisfy Rudy, they can satisfy the President," a person familiar with the meeting said.

Trump's push to have Giuliani as gatekeeper is more direct than what was previously disclosed by one of the meeting's participants in his statement to the House last week. It also further demonstrates how significant Giuliani was in brokering access to the President regarding Ukraine policy and in passing messages to other administration officials.

CNN has reached out to the White House for comment.

A key accusation in the whistleblower's complaint that has prompted the impeachment probe into the President's dealings with Ukraine is that Giuliani, a private citizen, had been presenting to Ukraine a US policy different than that from US diplomats.

Their goal was to tell Trump that they had a favorable impression of Zelensky and his government, and that he was a reformer who Trump should trust and engage with, according to three sources familiar with the meeting.

They were hoping to set up a meeting between Trump and Zelensky, the sources said. They believed Ukraine under Zelensky was a more trusted ally than previous Ukrainian regimes, and that a visit between Trump and Zelensky could demonstrate to the Russian government that the US embraced a free Ukraine, according to two of the sources.

Notably, Secretary of State Mike Pompeo was in Washington on May 23 but he did not attend the meeting with Trump.

Perry had led the delegation who attended Zelensky's inauguration, and was a central figure in the May meeting with Trump.

It became clear to the Trump administration officials, the sources said, that they would have to deal with Giuliani.

Volker hinted last week in speaking to the House how central Giuliani was in the President's foreign policy approach to Ukraine.

"The President was very skeptical," Volker said to the House committees, describing what had happened when he, Sondland and Perry spoke to Trump. "In the course of that conversation, he referenced conversations with Mayor Giuliani."

"He was clearly receiving other information from other sources, including Mayor Giuliani, that was more negative, causing him to retain this negative view " of a corrupt Ukraine, Volker added.

The US officials then set out to correct the information feed coming into the President while realizing they would need to work with --and around -- Giuliani, according to the sources.

Two months later, during an interagency meeting, the Office of Management and Budget announced it would review whether Ukraine should receive $400 million in assistance from the US that had been set aside by Congress. The question on aid that arose later eventually became a major topic of conversation among Sondland, Volker and others.

Perry acknowledged speaking to Giuliani, according to an Energy Department spokesperson. The spokesperson didn't comment on the meeting itself or the substance of the conversations with Giuliani.

When asked if he had ever spoken to Perry about Ukraine, Giuliani responded by dismissing the question.

"Did Henry Kissinger ever call me about Ukraine," Giuliani wrote to CNN on Tuesday. "What about Colin Powell."

He then said that any information about his possible discussions with Perry would be privileged. He did not explain why.