US President Donald Trump speaks during a meeting with Polish President Andrzej Duda on the sidelines of the UN General Assembly in New York, September 23, 2019.

The White House severely restricted distribution of memos detailing President Donald Trump's calls with foreign leaders, including Russia's Vladimir Putin and Saudi Arabia's Mohammed bin Salman, after embarrassing leaks of his conversations early in his tenure, a former White House official said.

The White House's handling of Trump's calls with foreign leaders is at the heart of House Democrats' impeachment inquiry. A whistleblower alleges the White House tried to "lock down" Trump's July 25 phone call with Ukraine's new president because officials were worried about Trump's request for help investigating Trump's Democratic rival Joe Biden. The anonymous whistleblower alleges the White House also tried to cover up the content of other calls by moving memos onto a highly classified computer system.

The former White House official acknowledged that other calls were concealed, while casting the decision as part of an effort to minimize leaks, not an attempt to hide improper discussions. The former official was not authorized to discuss the classification system publicly and spoke on condition of anonymity.

The White House was beset by leaks of highly sensitive information in the early days of Trump's presidency. Trump was particularly enraged by leaks that disclosed tough conversations with the leader of Mexico on paying for a border wall and with Australia on abiding by an Obama administration deal on asylum-seekers.