Sudanese authorities have put up barricades outside the military headquarters to stop protesters from gathering there.
Crowds are expected to mark a year since a violent crackdown by security forces in which more than 100 people were killed and 700 others wounded.
The uprising saw President Omar al-Bashir removed from power.
But many victims say those who replaced him are yet to deliver justice.
Al Jazeera’s Hiba Morgan reports from Khartoum.
– Subscribe to our channel: http://aje.io/AJSubscribe
– Follow us on Twitter: https://twitter.com/AJEnglish
– Find us on Facebook: https://www.facebook.com/aljazeera
– Check our website: https://www.aljazeera.com/