KAMPALA, Uganda (CNN) -- Two top Ugandan politicians seeking to unseat the African nation's President were arrested Thursday for allegedly defying orders to "stage illegal rallies not cleared by police," a top law enforcement official said.
Police operations chief Felix Kaweesi told reporters in Kampala that opposition leaders Kizza Besigye and John Amama Mbabazi had been told to either stay in their homes "or be put under preventive arrest." Neither politician ever staged or made it to a rally before being taken into custody.
Mbabazi's campaign issued a statement detailing his arrest around 9:50 a.m. (2:50 a.m. ET) en route to Mbale, "where he was scheduled to host his first consultative meeting." He was later driven back to the Ugandan capital of Kampala under police custody, while his daughter, Rachel Mbabazi, has been reportedly detained as well.
And Besigye's party, the Forum for Democratic Change, tweeted that he was arrested by Ugandan police "as he left his home ahead of his (campaign) launch in Kasangati." The party also posted a picture of one of the policemen trying "to stop @kizzabesigye1's launch" in Kasangati, which is a Kampala suburb.
Both Besigye and Mbabazi have signaled their intentions to run against Yoweri Museveni, who's led Uganda for nearly three decades.
A former defense minister turned guerrilla leader, Museveni became President after a 1986 coup and has been in that office ever since -- thanks in part to the Ugandan parliament's decision, in 2005, to remove presidential term limits. He has gained international attention for calling homosexuals "disgusting" and signing a 2014 law that toughens penalties against gay people, and he defines some homosexual acts as crimes punishable by life in prison.
A longtime opposition leader, Besigye has lost three presidential elections -- contesting the final results as flawed, albeit unsuccessfully.
Mbabazi was Uganda's Prime Minister until four months ago, when he was ousted from that position after protesting the ruling National Resistance Movement Party's decision to make Museveni its sole candidate in the 2016 presidential election.
Talking about Thursday's arrests, police spokesman Fred Enanga said, "We (did them) to avert a situation or crisis that the police feel may degenerate out of control," though he didn't specify what kind of dangers there were.
Journalist Samson Ntale reported from Kampala, and CNN's Greg Botelho wrote this report from Atlanta.
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