Republican presidential nominee Donald Trump is returning to Philadelphia Wednesday morning to discuss national security, military preparedness and veterans issues in a speech at the historic Union League.

The event is scheduled for 11 a.m. before an invited audience, and it is closed to the general public.

Trump's speech comes four days before the 15th anniversary of the 9/11 terrorist attacks. The New York businessman and Democratic nominee Hillary Clinton are scheduled to talk about security issues later Wednesday evening at a "Commander in Chief" forum hosted by  NBC and MSNBC.