Street children in Uganda face constant abuse from police and other government officials, a human rights group says.
Police beat children with whips and wires, throw them into jail and extort bribes from them, a report by Human Rights Watch (HRW) said.
Street boys and girls were also raped by men and older boys, it added.
A Ugandan official, Mondo Kyateka, said some street children were "hard-core criminals" but police only used minimum force against them.
The government should focus on improving the lives of street children, and prosecute those responsible for abusing them, HRW said.
More than half of all Ugandans are under 15, and children are the single largest group living in poverty, HRW said.
"Scores of street children told Human Rights Watch that they fear the authorities and that police are a source of violence, not protection," the group said in a report entitled "Where Do You Want Us to Go?"
It is unclear how many street children there are in Uganda, but one study, conducted in 2013, put the figure at around 10,000, it added.
Case study: Ignatius Bahizi, BBC Africa, Kampala, Uganda
Sempumba Paul, 16, is one of hundreds of children who live on the streets of Kampala. He told me he left his home about three years ago because his caretaker started mistreating him after the death of his parents.
Paul and his colleagues on the street normally fight for leftover food thrown in the garbage. They are always on the alert because Kampala city authorities come unexpectedly and round them up and take them to jail in a bid to get them off the streets.
Paul says they are often beaten up and sometimes they spend the day playing cat and mouse with city authorities.
Many children live on the streets because of poverty, or because their parents have died of HIV/Aids.
The rebellion in the north, waged by the Lord's Resistance Army (LRA), had also forced children to flee their homes, HRW said.
HRW interviewed more than 130 current and former street children from December 2013 to February 2014 in seven town centres across Uganda.
"For children to be effectively protected and cared for, the government should ensure that all children, including those on the streets, can find shelter and get an education," said Maria Burnett, HRW's senior Africa researcher.
"They should be treated with dignity and have the opportunity to find a safe way off the streets," she added.