Ugandan police briefly arrested opposition leader Kizza Besigye on Tuesday and said they would charge 15 protesters with treason in an effort to quell demonstrations against rising prices.
Deadly protests in April and May over soaring food and fuel prices were crushed by President Yoweri Museveni, who has been in power for more than two decades. Besigye was badly beaten and put under house arrest.
The protest movement, led by the Activists 4 Change (A4C)group, has struggled to rally large numbers since then, mainly because Besigye has largely stayed away from demonstrations.
On Tuesday, Besigye's party, the Forum for Democratic Change, said he was briefly arrested when he joined a walk-to-work protest on the outskirts of the capital, Kampala.
Later, police said the former presidential contender had been released and taken to his home in the Kasangati suburb.
Opposition youths reacted angrily to his detention, hurling rocks at passing vehicles. Police used teargas and water-cannon trucks spraying pink-coloured water to disperse the protesters.
Analysts said this opposition agitation was unlikely to grow into a serious threat to the government given the international community's muted response to the previous crackdown.
Police brutality in April and May was not punished and neither did we see strong condemnation of Museveni from the Western powers, and this discourages would-be protesters, said political analyst Nicholas Ssengoba.
Ugandan troops form the backbone of a peacekeeping mission in Somalia, a task few countries are willing to undertake.
Police said they had detained 45 opposition protesters since Sunday and would charge 15 of them with treason.
The police said they had unveiled a plot to overthrow the government. The opposition described the treason charges, which carry the death penalty, as flimsy.
Kale Kayihura, the inspector general for police, told reporters that security forces had obtained a recording of a September 23 meeting in which participants said they planned to use protests to topple the government.
We have arrested 45 people across the country so far and 15 of these will be charged with treason today or tomorrow, Kayihura said.
According to Kayihura, a person can be heard in the recording saying: The task remaining is how to bring down this regime and we must walk without stopping until the government falls.
Kayihura accused the group of seeking to plunge Uganda into lawlessness.
Clearly, as you can see, the whole intention of A4C's post-election campaign is geared at overthrowing the government through means other than what is provided for by the constitution of the republic of Uganda. This is a criminal offence called 'treason.'
Deputy foreign envoy for the Forum for Democratic Change (FDC), Ann Mugisha, dismissed Kayihura's accusation.
A4C is absolutely clear and unwavering in its commitment to non-violence in its activities. (The)Police just want to use serious charges to keep our activists out of action, she said.
Soaring consumer prices sent Uganda's inflation rocketing to 28.3 percent in September, its highest level since January 1993, fuelled by a weak local currency and high food prices.
Uganda, Africa's third-largest economy, hopes to become a top-50 oil producer in the next four years.