(CNN) -- Philadelphia police are investigating an incident caught on video and posted to the Internet in which a uniformed officer strikes a woman after he apparently was hit with a liquid.
The video, posted to YouTube, shows a crowd of people gathered around about a dozen officers handcuffing a man against a car at the annual Puerto Rican Day Parade on Sunday.
The woman, wearing a black shirt and jeans, is on the left side of the video and has a bottle in her left hand. The woman raises her left arm as she hops around behind one of the officers. Some liquid flies from the bottle at the police. The woman changes position and a man behind her tosses liquid at the police.
As the woman turns and retreats, an officer walks quickly after her and appears to strike her in the face with his right hand. The woman is knocked to the ground.
The man cuffs her and two other officers lead her away. She appears to have blood coming from her mouth.
Lt. Ray Evers, a spokesman for the Philadelphia police, said the woman was charged with disorderly conduct.
Police didn't release either the name of the woman or the officer.
Authorities had yet to determine the officer's duty status, Evers said.
Police asked witnesses who were at the parade to call 215-685-5056.
The video had almost 100,000 views and 2,500 comments by Monday evening.