President Donald Trump said Thursday he would never say anything "inappropriate" on a call with a foreign leader. Trump's tweeted statement Thursday comes as lawmakers look to scrutinize the handling of an intelligence whistleblower complaint that the Washington Post reported stemmed from a call Trump conducted with an unspecified foreign leader.The Post said Trump made an unspecified "promise" to the leader. The Associated Press has not confirmed the report by the Post, which cited two anonymous U.S. officials. Trump said that he understands that many people listen to those calls, adding "is anybody dumb enough to believe" that he would speak inappropriately under those circumstances. ....Knowing all of this, is anybody dumb enough to believe that I would say something inappropriate with a foreign leader while on such a potentially “heavily populated” call. I would only do what is right anyway, and only do good for the USA!—@realDonaldTrump He added that, "I would only do what is right anyway." The government's intelligence watchdog was set to testify Thursday in a closed session before the House intelligence committee about the handling of the whistleblower complaint. 'Credible and urgent' complaint: Schiff Intelligence committee chair Adam Schiff, Democrat from California, said inspector general Michael Atkinson determined the whistleblower complaint was "credible and urgent" and should be "transmitted to Congress." Atkinson is scheduled to testify Thursday. Joseph Maguire, acting director of national intelligence, has refused to discuss details. He is expected to testify publicly about the whistleblower complaint on Sept. 26. Schiff subpoenaed Maguire, saying he was withholding a whistleblower complaint from Congress and questioning whether he had been directed to do so by the White House or the attorney general. House intelligence chairman Adam Schiff has issued subpoenas to further investigate the matter, though a senior intelligence official said in a letter it did not rise to the level of being an 'urgent concern.' (Susan Walsh/The Associated Press) Schiff did not divulge the subject of the complaint, but said the committee "places the highest importance on the protection of whistleblowers and their complaints to Congress." In a letter Tuesday, the general counsel for the Office of the Director of National Intelligence (DNI), Jason Klitenic, wrote that the agency is protecting the whistleblower and argued the allegation does not meet the definition of "urgent concern." He said the complaint "concerned conduct from someone outside the intelligence community and did not relate to 'intelligence activity' under the DNI's supervision." Schiff said last week that Maguire is required to share the complaint with Congress and said the attempt to hold it back "raises serious concerns about whether White House, Department of Justice or other executive branch officials are trying to prevent a legitimate whistleblower complaint from reaching its intended recipient, the Congress, in order to cover up serious misconduct."