By Elias Biryabarema
KAMPALA (Reuters) - Ugandan police on Monday arrested 20 supporters and security guards at the headquarters of an opposition candidate vying to end the nearly 30-year rule of President Yoweri Museveni in elections next February, police and a campaign spokeswoman said.
The arrests underscored growing fears by rights groups and analysts that violence could break out in the East African country as 71-year-old Museveni faces his toughest challenge yet to extend his grip on power.
Amama Mbabazi, a former Museveni ally who previously served as prime minister, fell out with the president last year and has emerged as one of two formidable rivals, alongside long-time opposition figure, Kizza Besigye.
Most analysts, though, expect Museveni, who has previously been accused of using state resources and security personnel to promote his candidacy, to win the race.
A spokeswoman for the Mbabazi campaign, Josephine Mayanja-Nkangi, said that police had raided the campaign offices early on Monday and arrested security personnel and supporters.
Mbabazi was quoted by local television as saying that police had arrested "any male" they saw. "We condemn this outrageous behaviour by the state, this abuse of the state apparatus to promote the political agenda of a candidate contesting for elective office," he said.
Police spokesman Fred Enanga, said those who were arrested were suspected of taking part in a clash earlier this month between supporters of Mbabazi and Museveni in a southwestern village in where both campaigns were attempting to hold a rally.
"The ones we arrested have cases to answer," he told Reuters.
Uganda's opposition parties regularly complain of voter fraud, an accusation dismissed by the government. Besigye, who has run and lost to Museveni in three previous polls, has been arrested numerous times.
(Reporting by Elias Biryabarema; editing by Edith Honan and Dominic Evans)