Police today clashed with pro-democracy protesters in Hong Kong as they cleared an underpass near the government headquarters.
Hundreds of police officers wearing riot gear used pepper spray to disperse the protesters, and arrested dozens of people.
Police said Lung Wo Road had to be cleared as it was a major thoroughfare.
After the scuffles, police said officers involved in beating a protester would be reassigned.
Footage aired on local television earlier today showed a handcuffed protester being kicked and beaten by police officers during the operation.
Secretary for security Lai Tung-kwok said later that some officers seen on the video would be removed from their current duties and that an investigation would be carried out.
Demonstrators, a mix of students and a pro-democracy group called Occupy Central, have occupied parts of Hong Kong for more than two weeks. They are demanding fully free elections in the next vote for the territory's leader.
China, which has control over Hong Kong, says residents can vote - but it will vet which candidates are eligible to stand.
The footage shot by broadcaster TVB, showing a handcuffed demonstrator being punched and kicked by half a dozen police officers for several minutes, has been widely shared on social media.
Accusations of police using excessive force were made when authorities fired tear gas as the protests first erupted in late September. But this incident, which took place at around 3 am today, was different because the demonstrator, Ken Tsang, a social worker, had already been detained and no longer posed any threat to law enforcement.
Hong Kong's police force has for years prided itself on its professionalism, political neutrality and experience in crowd control. Now, citizens are asking, why did officers appear to behave with impunity toward a protester who had been subdued?