Ugandan police said Friday they had ordered a halt to public activities by opposition leader Bobi Wine's party after a deadly road crash ahead of a campaign event.

Three people were killed and "many others" injured in an accident involving cars and motorbikes that were part of a National Unity Platform (NUP) motorcade, police said.

"The police management has decided to halt any further consultative activities of NUP as a party with immediate effect until this matter is conclusively investigated and resolved," the Uganda Police Force said in a statement.

The accident took place as an NUP procession was headed to the city of Masaka southwest of the capital Kampala for a political rally, part of a nationwide "mobilisation" campaign ahead of elections planned for 2026.

Ugandan authorities have frequently cracked down on the NUP and Wine, a popstar turned politician who challenged President Yoweri Museveni in the last elections in 2021.

"The loss of the innocent lives was a result of recklessness of the drivers and riders who were driving in excess speed without regard to other road users," police said.

Wine said on X that the Masaka rally took place despite efforts by the authorities to disrupt it, with police hurling "sound bombs and tear gas canisters".

Pictures posted on his X feed showed riot police with helmets and shields amid clouds of smoke at the rally, and Wine -- whose real name is Robert Kyagulanyi -- addressing a vast crowd of supporters.

Police officials had met with NUP leaders earlier this week to discuss how the party should "conduct their consultative meetings," the police statement said.

"NUP have disregarded the agreed position and continue to act with impunity as demonstrated in today's unfortunate incident at Maya," it added, referring to the site of the crash on the road between Kampala and Masaka.

Opposition parties have been kept on a tight rein Museveni who has ruled Uganda with an iron fist since 1986.