Skateboarders clashed with police at San Francisco’s Dolores Park on Tuesday after a skater appeared to be dangerously taken down by a police officer. Video of the incident showed the high-speed skater smashing into a police car after an officer pushes him.

The incident happened after police turned up at an event known as The Hill Bomb, an annual competition in which skaters race down a steep hill, reported Hoodline. Video of the event, which runs without a permit, shows a heavy police presence lining the route.

💉💉💉 wishing Phelps and everyone else that slammed a speedy recovery. Wow! #bombhills A post shared by BLOOD WIZARD (@blood_wizard) on Jul 11, 2017 at 11:11pm PDT

Today was maxed out A post shared by Quiante R. Hoggard (@og_qui) on Jul 11, 2017 at 11:03pm PDT

Following the clash between a skater and an officer, tension rose at the event, according to reports on Twitter and Instagram, with bottles thrown into the crowd and reports of police firing beanbags.

The situation escalates as people throw bottles into the crowd A post shared by Matt Harris (@mattleeharris) on Jul 12, 2017 at 12:08am PDT

Dolores Park tuesdays - guy smashes police car window with a skateboard, police shooting beanbags pic.twitter.com/oIMbog9g2e — Lance Martin (@RLanceMartin) July 12, 2017

A tweet from police asked the public to avoid the area following the clashes.

Large police presence to Dolores Park due to injured officer & request for crowd control; #SFPD officers were taking projectiles from crowd. — Ofc. Grace Gatpandan (@OfficerGrace) July 12, 2017

An officer can be seen carrying a shotgun at the event in a video posted to Twitter by Joel Hamill. A voice can be heard saying “they are filming you,” seemingly warning the officer.

RT.com reached out to uploaders of content from the incident but have yet to receive a response.

One competitor at the event was filmed suffering a severe fall. He was seen unconscious, lying on the ground and in need of medical attention.

The homie Phelps took a fucking hard slam at the Dolores downhill. Let's 🙏🏼 is Ok... #SkateAndDestroy #Hellride #Pray4Phelps A post shared by Chico Brenes (@chicobrenes) on Jul 11, 2017 at 9:23pm PDT