Police arrested Uganda's leading opposition figure on Monday saying he was about to stage illegal rallies, in what will be seen as the latest crackdown on dissent in the oil-rich African country.
Kizza Besigye has been detained several times since he championed opposition demonstrations that rocked parts of the capital and other cities during 2011 elections.
A security crackdown on those protests left at least nine people dead and tarnished the image of veteran President Yoweri Museveni.
Opposition activists last week said they were planning more rallies against what they saw as unfair taxes on piped water and kerosene.
"The law allows us to carry out preventive arrest," deputy police spokesman Patrick Onyango told Reuters.
"We had information that Besigye was leaving his home to commit crimes by staging illegal assemblies and we arrested him," he added.
One of Besigye's aides, Francis Mwijukye, told Reuters the opposition leader had been taken to a prison in Mukono district, about 40 km (25 miles) east of the capital Kampala.
"They're scared that holding him in Kampala is dangerous because his supporters would come to demand his release. So they abducted him and brought him to a rural area," he said.
Museveni won local and international praise in the years after he took power in 1986 for stabilising the country and spurring growth in.
The prospects of Uganda, east Africa's third largest economy, looked brighter still when explorers struck oil in 2006. Uganda said in January it was aiming to start commercial output of oil by 2016 at the earliest.
But the president has faced mounting criticism for what opponents say is an increasingly authoritarian style.
Besigye, a one-time ally of Museveni, has traditionally drawn most of his support from urban centres while Museveni has broadly remained popular among the rural masses.