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A whistleblower complaint filed on Aug. 12 by an official in the U.S. intelligence community involves President Trump's communications with a foreign leader, two former U.S. officials familiar with the matter told The Washington Post on Wednesday.

During the interaction, Trump made a "promise" to the foreign leader that the whistleblower found so troubling they decided to file the complaint to Intelligence Community Inspector General Michael Atkinson, the Post reports. In turn, Atkinson found the complaint worrisome enough that he marked the matter of "urgent concern" and submitted it to acting Director of National Intelligence Joseph Maguire. Maguire replaced former DNI Dan Coats, who resigned in August.

By law, Maguire was supposed to send the complaint on to Congress, but after asking Justice Department officials for legal guidance, he refused, the Post reports. The House and Senate intelligence committees only learned of the complaint after Atkinson, not Maguire, notified them earlier this month, though he did not say what was in the complaint. House Intelligence Committee Chair Adam Schiff (D-Calif.) is trying to get intelligence officials to share the details with lawmakers, and Atkinson is scheduled to appear before Schiff's committee for a private session on Thursday.

One former official told the Post the communication in question was a phone call. It's not immediately clear which foreign leader Trump was speaking to or what he promised them. In the five weeks before the complaint was filed, White House records show that Trump spoke and interacted with at least five foreign leaders, including Russian President Vladimir Putin and North Korean leader Kim Jong Un.