Source: Mike Pompeo was on Trump's July 25 phone call with Ukrainian President

Secretary of State Mike Pompeo was on the July 25 phone call between President Donald Trump and Ukrainian President Volodymyr Zelensky that has come under scrutiny following last week's release of a whistleblower complaint dealing, in part, with circumstances surrounding that conversation, a source familiar told CNN.

A rough transcript of the conversation released by the White House shows Trump repeatedly pushed Zelensky to investigate former Vice President Joe Biden and his son Hunter.

During that call, Trump asks Zelensky to speak with his personal lawyer, Rudy Giuliani, and suggests that the Ukrainian President "look into" Biden and his son.

"There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the attorney general would be great. Biden went around bragging that he stopped the prosecution so if you can look into it. ... It sounds horrible to me," Trump said, according to the White House transcript.

There is no evidence of wrongdoing by either Joe or Hunter Biden.

The Wall Street Journal first reported that Pompeo was on the July 25 phone call between the two leaders. The State Department has not yet responded to CNN's request for comment.

Pompeo was asked about the whistleblower complaint last week while in New York for the United Nations General Assembly and said at the time he had not yet read it in full. When asked if he or his staff acted improperly Pompeo did say that, to the best of his knowledge, "each of the actions that were undertaken by State Department officials was entirely appropriate."

The top US diplomat offered a similar response during an ABC News interview eight days ago when questioned about the complaint and reports that Trump had repeatedly pressed the Ukrainian leader to investigate the Bidens with help from Giuliani.