House Democrats launched the impeachment investigation last week after the White House initially tried to block Congress from seeing a whistleblower complaint filed by a member of the US intelligence community involving a July phone call between Mr. Trump and Ukrainian President Volodymyr Zelensky.
Johnson defended Trump's request for Ukraine to investigate his potential 2020 political opponent Joe Biden.
The inquiry reached deeper into the White House when the House sent a letter on Friday to Mr Trump's acting chief of staff Mick Mulvaney, informing him that the White House was being subpoenaed for documents it had refused to produce.
Trump's comments came shortly before the Democrats sent an extensive request for documents from Vice President Mike Pence about his contacts with Ukraine.
The White House also faces a Friday deadline, set down by House Democrats, to comply with requests for documents related to Trump's efforts to pressure Ukraine or face a subpoena.
In addition to Pompeo, the committees have also subpoenaed Trump's personal attorney Rudy Giuliani and the White House.
The White House sought to play down the issue of the subpoena, saying it "changes nothing".
Trump argued that it was normal for him to raise the issue of Biden in the phone call and that he had spoken to the public many times on the issue as well.
"I think everything's a question of priorities".
Speaking to reporters on Friday, Biden said to "focus on this man and what he is doing" when asked if there was a conflict of interest in Hunter Biden serving on the board of a Ukranian energy company while he was vice president.
"What we're talking about here is not about personality, it's not about policy differences - that's to be taken up in the election", Pelosi said.
In a tweet early Saturday, Trump said that "the so-called Whistleblower's account of my flawless phone call is 'way off, ' not even close".
Michael Atkinson, the general inspector of the intelligence community, interviewed this official to corroborate the original whistleblower's allegations, the paper reported. The July 25 call has since triggered an impeachment inquiry against Trump.
A Republican senator said Friday he learned from a USA ambassador that President Donald Trump was tying military aid for Ukraine to an investigation of the 2016 election.
When Pelosi recently announced that the House was initiating the inquiry, she didn't seek the consent of the full chamber, as was done for impeachment investigations into former Presidents Richard Nixon and Bill Clinton.
Trump has openly called on Ukraine and China to investigate the Bidens, asserting on Thursday that he has the "absolute right" to ask "other Countries" to investigate corruption, amid escalating scrutiny over his interactions with foreign leaders.
And he supplied them with dozens of text messages in between USA diplomats in Ukraine talking about how to cope with a response to Trump's requires that the nation investigate Biden.
Democrats accused Trump of speeding down "a path of defiance, obstruction and cover-up".
House Democrats subpoenaed the White House for documents on Friday.
In a signal of how Kiev will handle investigations being watched in Washington, Ukrainian prosecutors said they would review 15 old probes related to Burisma's founder but added that they were unaware of any evidence of wrongdoing by Biden's son. One deposition that is confirmed - that's an interview with the former US ambassador to Ukraine, Marie Yovanovitch.