Donald Trump’s campaign was warned about not taking photographs before an altercation at Arlington National Cemetery during a wreath-laying ceremony earlier this week to honor service members killed in the Afghanistan War withdrawal, a defense official told The Associated Press on Wednesday.

The official spoke on condition of anonymity to discuss a sensitive matter concerning Monday’s events. It came a day after NPR reported, citing a source with knowledge of the incident, that two Trump campaign staff members “verbally abused and pushed” aside a cemetery official who tried to stop them from filming and photographing in Section 60, the burial site for military personnel killed while fighting in Afghanistan and Iraq.