Nathan Nandala Mafabi, the secretary general of the Forum for Democratic Change (FDC) spent Friday night in the cells of Tororo Central Police Station.
Mafabi was picked up by police from Mbale town on Friday afternoon on his way to his constituency in Budadiri West to consult on the proposed presidential age limit removal.
He was driving in his vehicle accompanied by his supporters dressed in red T - shirts and ribbons on their head when they were intercepted by police.
Mafabi was given a huge reception by hundreds of people who waited for him at Doko and Kamonkoli, a few kilometres outside Mbale town.
He drove through Bishop Wakisye road, Market Street, Republic Street and joined Kumi road to connect to his constituency.
Police first intercepted Mafabi's convoy at Kayira Complex along on Kumi road, leading to a fierce scuffle between his supporters and the officers.
Police used teargas to disperse Mafabi's supporters as he drove off towards to his constituency until he was intercepted in front of the main gate of Islamic University in Uganda.
Police then arrested Mafabi and whisked him off to Mbale Central Police Station before he was transferred to Tororo Central Police Station in Tororo town.
Police also picked up Emmanuel Masaba Sabunyo, the former Bulambuli county FDC parliamentary candidate and former councillor, Abdullah Magombe.
Two people including a pupil of Tower Primary School were injured by the teargas canisters fired by police.
