A New York City police officer suffered lacerations to his hand at Zuccotti Park during a mass protest.
Mayor Michael Bloomberg and police commissioner Ray Kelly said at a press conference that the officer was cut after making a "defensive manoeuvre" with his arm. Five officers were also attacked with a "vinegar-like substance", Kelly said.
Kelly said that 177 people had been arrested, including five on charges of second-degree assault.
Protesters were also reported to have suffered injuries at the park as the 'day of action' in the city appeared to take an ugly turn.
Al Jazeera English reported that a protester was taken away with his head "covered in blood".
The day began with thousands of protesters attempting to shut down the New York Stock Exchange. The Stock Exchange opened on time at 9.30am but the protests continued throughout the day, with more than 100 reported arrests.
Protesters later gathered in Union Square while planning to march downtown and across the Brooklyn Bridge.
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