The comment came in a tweetstorm voicing outrage over a recent New York Times report saying days after the May 2017 firing, the Federal Bureau of Investigation opened an inquiry into whether Trump was "secretly working on behalf of Russian Federation".
Pompeo, a former Central Intelligence Agency director, was one of a number of Trump administration officials to blast the revelations contained in the Times' report.
Although the FBI used Comey's firing as a justification for the investigation, according to the Times, at the time agents were already concerned over the president's links to Moscow.
President Donald Trump had a scathing rebuke of the FBI after learning on Saturday that as part of the Russian Federation investigation, officials opened a counterintelligence inquiry into whether he worked on Moscow's behalf.
According to Trump, "the FBI was in complete turmoil ... because of Comey's poor leadership" and the way he handled the investigation into Hillary Clinton's use of a private server to send some government emails.
The counterintelligence angle comprised of deciding if Trump was intentionally or unconsciously working for Moscow and whether he was a danger to national security, the paper revealed.
In a statement, released Friday night, White House Press Secretary Sarah Huckabee Sanders slammed the report, calling it "absurd" while claiming that Trump has been tough on Russian Federation, unlike his predecessor former President Barack Obama.
According to the New York Times, top FBI officials had already grown suspicious of Trump during the campaign but at first balked at starting a counterintelligence investigation, in part because they were "uncertain how to proceed with an inquiry of such sensitivity and magnitude".
The paper says the FBI investigation was rolled into the work of special counsel Robert Mueller, who is leading an inquiry into whether Mr Trump's campaign and transition teams colluded with Moscow to influence the 2016 United States election. The Times previously reported that Deputy Attorney General Rod Rosenstein, who appointed Mr. Mueller rather than keeping the Russian Federation probe in-house, talked of wearing a wire when he met with the president.
Officials reportedly held off on investigating Trump during the campaign but chose to initiate the counterintelligence aspects amid former FBI Director James Comey's firing in May 2017. It is not clear whether Mueller pursued the matter.
As for Manafort, two pro-Russia Ukrainian oligarchs were the intended recipients of U.S. polling data that Manafort admitted to sharing with a Russian during the 2016 presidential race, CNN reported.
Mr Trump's lawyer Rudy Giuliani told the Times that he had no knowledge of the inquiry but said that since it was opened a year and a half ago and they had not heard anything, apparently "they found nothing".