Uganda's largest opposition party threatened on Tuesday to prevent presidential elections from being held early next year if the government rejected its demand for an independent electoral commission.
President Yoweri Museveni, who will have been in power for 30 years in 2016, is widely expected to stand for another five-year term despite widespread criticism of authoritarianism and failure to tame deep-rooted corruption.
Francis Mwijukye, deputy spokesman for Forum for Democratic Change (FDC), told Reuters the party wanted the commission to compile a new and accurate voters' register before the polls.
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"Uganda's constitution talks about a free and fair election. Anything less would be illegal," Mwijukye said.
"Our position is that unless we have an independently constituted electoral commission and a new voters' register, we won't allow an illegal election to take place."
He declined to say how the party would prevent the vote.
The commission said it had updated the voter's register and added new voters this year, and that parliamentary and presidential elections would be held in February or March 2016.
The electoral commission has in the past drawn accusations of incompetence and favouritism toward Museveni, who appoints its chairman and other top officials.
FDC, other opposition parties and civil society groups say the government must amend the election laws to allow a judicial body to appoint electoral commission officials to guarantee their independence.
FDC and the party's former leader Kizza Besigye led anti-government protests after the 2011 elections alleging vote rigging, high consumer prices and rampant corruption.
Besigye has stood against Museveni three times and lost.
In two of the polls, he appealed to Uganda's supreme court to overturn the results. While a majority of judges agreed with him that there had been rigging, they said the vote theft was not substantial enough to affect the outcome.
Besigye has not indicated whether he will run again in 2016.
Betty Nambooze, a legislator from the opposition Democratic Party, said they would push for an independent poll body and voters' register but that they would not support a boycott or sabotage of the elections.
"We need to participate so that if they rig, we use that as a trigger to get people on the streets and sweep the dictator away," she said.
Economic analysts have said the uncertainty surrounding the elections was likely to rattle investors.
"No one can stop these elections, the poll will take place with or without so called electoral reforms," government Spokesman Ofwono Opondo said.