Ugandan soldiers beat up the pop star-turned lawmaker and squeezed his genitals until he lost passed out- A doctor later told him that one of his “kidneys … had been damaged during the assault.

my brother was among the people the who badly beaten with the Honorable member of parliament. he was badly beaten and we have no money to pay for his treatment.

Robert Kyagulanyi, a Ugandan pop star-turned-opposition politician, has alleged that security officers beat him up and squeezed his genitals until he passed out while in detention, in his first public statement since his arrest last month.

Kyagulanyi, whose stage name is Bobi Wine, was held on August 14 and charged with treason over his alleged role in the stoning of President Yoweri Museveni's car during a by-election campaign.

The 36-year-old, whose case has drawn international attention, was released on bail nearly two weeks later. But Kyagulanyi was rearrested last week while trying to leave the country to seek medical treatment in the United States

In a lengthy statement posted on Facebook on Monday, Kyagulanyi wrote that he wanted to "set the record straight".

"They wrapped me in a thick piece of cloth and bundled me into a vehicle. Those guys did to me unspeakable things in that vehicle! They pulled my manhood and squeezed my testicles while punching me with objects I didn't see," Kyagulanyi alleged.

"They beat me, punched me, and kicked me with their boots. No part of my body was spared. They hit my eyes, mouth and nose. They hit my elbows and my knees," he added.

"By the time I became conscious again, I was somewhere in a small room with a small window. My legs were tied together with my hands with very tight cuffs. I was bleeding from the nose and ears. I was in great pain. The cloth they had tied me in was red-soaked in blood. My whole body was swollen."

Kyagulanyi also wrote that a radiologist told him "how one of my kidneys and back had been damaged during the assault. I was however not given any written medical report by the military".

Soldiers were sent to Kampala's streets to put down protests by Bobi Wine's supporters [File: AP]

Popular figure

Kyagulanyi's arrest sparked protests in the capital, Kampala, and elsewhere demanding his release, with scores of people detained.

A social media campaign to #FreeBobiWine was launched, while scores of musicians, activists and politicians signed an open letter condemning Kyagulanyi's treatment. Rights groups also urged the president to arrest the alleged perpetrators and present them in court.

The treason charges, also faced by 30 others people, including legislators, have heightened concerns about a crackdown on the opposition in Uganda.

On Monday, Ugandan authorities charged a fifth legislator, Francis Zaake, with treason, which carries a maximum death penalty. The lawyers of those accused have denied the allegations.

Kyagulanyi has emerged as a powerful opposition voice among youths frustrated by Museveni's 32-year rule, especially after the constitution was changed last year to remove an age limit on the presidency.

The singer won a parliamentary seat last year without the backing of a political party.

His supporters, citing his success in helping opposition candidates to win elections across the country, are urging him to run for president in 2021.