Leading Ugandan opposition figure Dr Kizza Besigye was arrested on Tuesday as he tried to lead a protest in the capital, Kampala, against the high cost of living.
The 66 year old ran for the presidency against Yoweri Museveni four times.
He used to be Mr Museveni’s personal doctor and has been arrested on many occasions.
Dr Besigye arrived at Tuesday’s protest with megaphones on his car and he caused business in the local area to come to a standstill, according to the Daily Monitor news website.
Ugandan police told the Reuters news agency that they are holding Dr Besigye on charges of inciting violence.
He has not yet commented.