At least nine people were killed in demonstrations and Kizza Besigy , theForum for Democratic Change president was arrested and beaten by security agents.
"We didn't allow the crowd to grow big because we wanted to prevent the worst from happening ... we were not opposed to the rally but they refused to listen to us on the venue where they should stage it," said Ibn Senkumbi, a police spokesman at the scene.
A heavily deployed police managed to disperse the crowd of several hundred people.
Anne Mugisha, deputy foreign secretary for the Forum for Democratic Change, the largest opposition party, criticised the heavy-handedness of police, saying they were intent on "disrupting and criminalising" the event.
"The issue wasn't really a disagreement about the venue. Police deployed early and turned Kireka town into a battlefield. They were determined to fight and as usual they found an excuse to brutalise peaceful activists but we're not deterred a bit," she said.
Though protests have died down since the April-May violence, strikes by teachers, traders and taxi drivers -- incensed at double-digit inflation and a record-low shilling -- have increased in recent weeks.
Police fire teargas, disperse protesters