The Post has contacted the force seeking comment.

About 8,000 people – some 40 per cent of them students – were arrested during months of social unrest that erupted last June over a now-withdrawn extradition bill, while at least 1,365 people were prosecuted.

Those interviewed by Civil Rights Observer were arrested at protests that took place between July and November. Real names and exact times of arrests were not included in the report to avoid potential retribution.

Coronavirus: Hongkonger without travel history confirmed as infected after 22 days without any new local cases

Thirteen of the arrestees reported severe assault or injuries at the hands of the police; 16 said access to their lawyers was delayed; and three claimed they were sexually assaulted.

One of the alleged victims, identified by the pseudonym Gabriel in the report, accused officers of planting a brick on him and repeatedly hitting his fingers, arm, pelvis and head with batons. Officers also slammed his head into the door of a police van a dozen times, he claimed.

After being taken to the station, three officers then took turns hitting him in the stomach for 15 minutes, while another officer covered his eyes, slapped his face and kicked his abdomen as he was questioned, according to the report. Gabriel was subsequently sent to the hospital directly from the police station and treated in a neurosurgery ward.

Another person, identified as Jason, claimed he was taken to a police station for taking video footage at a protest. He alleged that a plain-clothes officer then hit him in the head and shined a flashlight in his eye for about 15 seconds.

Police chief Chris Tang admits handling of journalists covering Mother’s Day demonstrations was unsatisfactory

“Don’t you like to shine light at things? If I do this to you for a minute, you will become blind,” he quoted the officer as saying.

Wong said the alleged incidents could amount to prima facie cases of assault occasioning actual bodily harm as well as violations of international human rights agreement, such as the UN Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment.

Andrew Shum Wai-nam, another member of the group, said: “We urged the government to set up an independent inquiry to look into the allegations against police brutality, as well as to hold individual officers involved accountable.”

He added that surveillance cameras should be installed inside police vehicles to prevent any maltreatment, something recommended by a 2018 coroner’s inquest that followed the death of a man inside a police vehicle.

Hong Kong government to expand HK$80 billion wage subsidy scheme to include seniors and vulnerable

The group said it will submit the report to the United Nations Human Rights Committee – which is holding a hearing on Hong Kong next month – as well as legislatures in Britain and the United States.

Meanwhile, the pro-establishment camp, which has traditionally ignored meetings of UN bodies, has joined the fray this year.

Hong Kong Higher Education Convergence, a Beijing-friendly group, has tabled a submission to the UN Human Rights Committee condemning violence committed by masked protesters last year.

It expressed support for the police in its submission, saying the force had used only necessary force to restore law and order and had not killed a single person – unlike protests in other countries.

The group also argued the city’s anti-terrorism laws were not comprehensive enough, saying police should be allowed to detain those suspected of terrorist activities for up to seven days as well as stop and search without grounds of suspicion.