Police said that Mr Kyagulanyi was arrested for violating the Electoral Commission guidelines as he had more than 200 people at the rally.
According to the Electoral Commission, presidential candidates are not supposed to hold rallies or processions during campaigns but are allowed to hold meetings of not more than 200 people during their campaigns.
Protests broke out Wednesday in parts of Uganda's capital Kampala after supporters of Ugandan pop star turned politician Robert Kyagulanyi, popularly known as Bobi Wine, learnt of his arrest.
Police fired teargas and rubber bullets as the politician's supporters engaged them in running battles, demanding for Bobi Wine's unconditional release.
Mr Kyagulanyi was arrested in the country’s eastern district of Luuka during a campaign rally for violating the Electoral Commission guidelines on the number of people who should be present during candidates' campaigns.
According to the Electoral Commission, presidential candidates are not supposed to hold rallies or processions during campaigns but are allowed to hold meetings of not more than 200 people during their campaigns. Police said more than 200 people were present in Mr Kyagulanyi's meeting.
Police fired tear gas at the rally venue and some of the politician's aides were injured in the ensuing scuffle.
Two journalists were beaten and one arrested at the scene.
Mr Kyagulanyi, the presidential flag bearer of the National Unity Platform (NUP), together with nine other presidential candidates are traversing the country to seek votes ahead of the January 2021 election.
NUP Secretary General Lewis Rubongoya said that it was the police’s work to manage the crowd, adding that they should not arrest the presidential candidates.
Earlier on Wednesday, Inspector General of Police Okoth Ochola had warned that the force had adopted a tougher approach to candidates that flaunt the guidelines. He added that unauthorised assemblies would not be permitted.
“Therefore, those who shall defy these Electoral Commission guidelines with their sinister plans aimed at disrupting the electoral process will definitely suffer consequences,” Mr Ochola said.
For the nine days of the campaign so far, police have often fired teargas to disperse opposition supporters mostly in processions with their candidates.
At least three of the opposition candidates have also been blocked from campaigning in certain areas.
