Voting is under way in a controversial by-election in the north-west Ugandan town of Arua.
Dozens of people were arrested ahead of the vote, including the main opposition candidate and one of his key supporters – the popular Afrobeats musician and MP Robert Kyagulanyi, known as Bobi Wine.
They were arrested after a vehicle in President Yoweri Museveni’s convoy was attacked late on Monday.
Wine’s driver was later shot dead.
The by-election is taking place because the previous MP for Arua, Ibrahim Abiriga, was shot dead in June in still unexplained circumstances.
So far there are reports of a low voter turnout in Arua, which is a regional hub close to Uganda’s borders with South Sudan and the Democratic Republic of Congo.
The opposition in Uganda has long accused President Museveni of using the military and police to influence the outcome of elections.
He denies the allegation.