New York City police say an off-duty officer was being assaulted when he drew his gun during Tuesday's protest against police brutality. He was treated for bruises at an area hospital and released.

The march was organized by National Actions to Stop Murder By Police and was part of a coordinated series of demonstrations around the country.

Gothamist first reported the story.

The demonstration was largely peaceful, but became tense when protesters swarmed the Brooklyn Bridge. A total of 42 people were arrested.

Mayor de Blasio later released a statement condemning the violence.

With reporting from the Associated Press.