According to Human Rights Watch (HRW), Rwandan police are arbitrarily detaining vulnerable people picked up on the streets of the capital.

The US-based campaign group says Kigali's reputation for being tidy comes at a price. It also went further to state that it has documented the illegal detention of thousands, including street children and sex workers.

The organisation says the rounding up of street vendors, beggars, homeless people, street children, sex workers and petty criminals reflects an unofficial policy of keeping those considered undesirable away from the public eye.

HRW says detainees are held there in deplorable conditions for periods ranging from a few days to several months.

Former detainees told HRW of routine beatings for actions as trivial as talking too loudly or not standing in line to use the toilet.

Carina Tertsakian, who put together the report, says the Rwandan authorities should immediately close the detention centre and release all the detainees.

"If some of these detainees are suspected of committing a criminal offense they should be brought to justice according to the law," she added.

Rwanda's justice minister told HRW in 2014 that the place the people have been taken is not for detention, but is there to provide rehabilitation that avoided "unnecessary incarceration".