Clashes between protesters and authorities marred the 2006 election, and Museveni's main rival, Kizze Besigye, last week warned more trouble was likely. He accused Museveni's ruling party of planning to rig the polls.

"I cannot be defeated in these elections," Museveni said on the state-run Bukedde TV Sunday evening. "If the chaos gets out of hand, I will use the army."

The opposition claims people are storing food in anticipation of widespread protests. Museveni, who came to power in 1986 following a coup, is favoured to win given the weak and divided nature of the opposition in the East African nation.

Besigye, a retired army officer and former Museveni ally, leads a coalition of opposition parties and was runner-up in 2006.