The standoff between police and protesters in Hong Kong has turned ugly. Police forces have started clearing street barricades from some of the protest sites and in the early hours of Wednesday morning, the police violently beat a demonstrator.

The whole scene was caught on video.

Protesters had blocked the tunnel of a major roadway near the office of Hong Kong’s chief executive. Police deployed a large force to disperse the demonstrators and open up the road. Scuffles broke out between protesters and officers, who used pepper spray and made 45 arrests.

The video shows a protester in handcuffs being dragged away and then beaten by a half-dozen police officers for several minutes.

A spokesman for the Hong Kong police said protesters near the government office had acted aggressively by kicking and attacking officers with umbrellas. But protest leaders and their supporters have decried what they see as excessive force by police. Human Rights Watch released a statement saying “the excessive force used against peaceful protesters who are not resisting is utterly unacceptable.”

The man being beaten by police in the video has been identified as Ken Tsang, an employee of one of Hong Kong’s pro-democracy political parties. He said he was “brutally” assaulted and that he might pursue legal action against the police. Pictures of his injuries have been disseminated online.

Images of beating victim Ken Tsang, a Civic Party activist. #occupyHK pic.twitter.com/1vVnceVikF — Tom Grundy (@tomgrundy) October 15, 2014

The police say an investigation will be conducted.

Here’s a video shot by The World’s Matthew Bell over the weekend about 44-year-old activist and artist Kacey Wong at a protest site in the Mong Kok neighborhood of Hong Kong.