White House lawyers briefed President Trump in late August of the whistle-blower complaint about his telephone conversation with President of Ukraine Volodymyr Zelensky on July 25, The New York Times has reported, referring to the sources familiar with the matter.

According to two interlocutors of the publication, President Trump was briefed on a whistle-blower's complaint about his dealings with Ukraine in late August, explaining that they were trying to determine whether they were legally required to give it to Congress.

At the same time, military assistance for Ukraine was unfrozen in September, the newspaper says.

Additional details about the suspension of military assistance to Ukraine became public on Tuesday in connection with the release by the House of Representatives of transcripts of interrogations of witnesses as part of the Trump impeachment process.

Thus, an official from the White House budget office, Mark Sandy, testified that on July 12, he received an email from the office of the acting White House chief of staff, Mick Mulvaney, notifying him that Mr. Trump had directed that administration officials freeze Ukraine's military aid.

Democrats in the U.S. House of Representatives on September 24 initiated an impeachment inquiry against Trump following a whistleblower report of the July 25, 2019 telephone conversation between Trump and Ukrainian President Volodymyr Zelensky. The memorandum of the call shows Trump asking Zelensky the investigation into the son of former U.S. Vice President Joe Biden, his likely opponent in the 2020 U.S. presidential elections, and his son Hunter. U.S. media reported that Trump "froze" military aid for Ukraine to put pressure on Zelensky.