|Besigye recently stepped down as leader of his party to focus on organising more anti-government protests [Reuters]
Kizza Besigye, an opposition leader, and several of his allies have been held by authorities in Uganda, who say they did so in order to prevent an anti-government rally that would cause unrest.
Police fired teargas and held the opposition leaders, who they intercepted on a highway in Kampala, on Thursday.
Besigye had been meeting a number of senior opposition leaders in an upmarket suburb of the capital, ahead of a rally to demonstrate against corruption and economic hardship.
Armed police fired a single tear gas canister at the group, ending what had become a protracted standoff, and then bundled the opposition leaders into a van. The protest failed to go ahead.
"We're holding Besigye and others as a preventive measure because there was a likelihood of a breach of peace and chaos," deputy police spokeswoman Judith Nabakooba told reporters outside the city police station.
"We'll hold [them] until we're sure there is no more threat."
Besigye, who served as President Yoweri Museveni's doctor during the war that propelled him to power and later as a minister in his government before the pair fell out, told Reuters last week that he would quit as head of his party to devote more time to planning protests. He has lost three presidential elections to Museveni.
Museveni, in power since 1986, has cracked down hard on a wave of protests against rising prices that started last year. At least 10 people have been killed, and hundreds more arrested.
Besigye himself was arrested several times during violent clashes between security forces and his supporters. In one of the protests, he was pepper-sprayed in the eyes and badly manhandled, after which he required hospital treatment in neighbouring Kenya.
Police have placed several leading opposition politicians under de facto house arrest to prevent them from joining or organising demonstrations.
The opposition-led Activists 4 Change group, which spearheaded those protests with Besigye, accused the government this week of "failed economic policies" that the group said had allowed the cost of living to soar.
Last week, a three-day strike over high interest rates by shopkeepers in Kampala bought business to a standstill, while the government's cutting of power subsidies sparked outrage as prices rose by over a third.