Hundreds marched across the Brooklyn Bridge in New York City in a massive show of mourning for Floyd, who died May 25 while in Minneapolis police custody.
Dermot Shea said protesters were not seriously injured, but officers have been shot at, stabbed and otherwise.
NBC News' Gabe Gutierrez speaks to David Williams, an eye witness to the moment George Floyd died in police custody, about what he saw on the scene.
The ship, which was near Jacksonville, was scheduled to leave the area when the explosion occurred.
The altercation on the Capital Crescent Trail in Bethesda was caught on video.