Hundreds of protesters gathered in New York City on Tuesday night to march against police brutality.

The march was organized by National Actions to Stop Murder By Police. Many of the protesters cited the deaths of Eric Garner in Staten Island and Walter Scott in South Carolina.

The protesters marched from Manhattan's Union Square and across the Brooklyn Bridge where they partially blocked traffic. Several people were seen getting arrested, but police said early Wednesday that information on the number of arrests was not yet available.

Police say an off-duty police officer driving home on the bridge was assaulted by two protesters when he got out of his vehicle to investigate. Police say the suspects ran off after he identified himself as a police officer. He was hospitalized with injuries to his face and arm.

Mayor Bill de Blasio released a statement condemning the violence.

Last year, two officers were assaulted on the bridge during a protest over Garner's chokehold death. Seven people were seen on amateur video pushing, kicking and punching the two officers. Five people were later arrested in that assault.

Organizers say Tuesday's protest was one of 28 being held across the country.