U.S. National Security Advisor Mike Waltz received emails via his personal email account but has never used that account to send classified material, the White House said after The Washington Post reported Waltz and other National Security Council members used Gmail for government work.

Senior members of the Trump administration’s National Security Council — including its top national security adviser, Michael Waltz — used Gmail to conduct government business, The Washington Post reported, citing documents and three unnamed government officials.

The Gmail accounts were used to discuss “sensitive military positions and powerful weapons systems relating to an ongoing conflict,” according to the Post, citing three unnamed government officials and emails reviewed firsthand by the newspaper.