National Security Adviser H.R. McMaster mocked President Trump’s intelligence at a private dinner with a powerful tech CEO, according to five sources with knowledge of the conversation.

Over a July dinner with Oracle CEO Safra Catz — who has been mentioned as a candidate for several potential administration jobs — McMaster bluntly trashed his boss, said the sources, four of whom told BuzzFeed News they heard about the exchange directly from Catz. The top national security official dismissed the president variously as an “idiot” and a “dope” with the intelligence of a “kindergartner,” the sources said.

A sixth source who was not familiar with the details of the dinner told BuzzFeed News that McMaster had made similarly derogatory comments about Trump’s intelligence to him in private, including that the president lacked the necessary brainpower to understand the matters before the National Security Council.